Editing Caligula (section)

== Emperor ==
=== Early reign ===

[[File:Eustache Le Sueur - Caligula Depositing the Ashes of his Mother and Brother in the Tomb of his Ancestors - WGA12607.jpg|thumb|upright|''Caligula Depositing the Ashes of his Mother and Brother in the Tomb of his Ancestors'', by [[Eustache Le Sueur]], 1647.]]

Tiberius died on 16 March AD&nbsp;37, a day before the [[Liberalia]] festival. He was 77 years old. Suetonius, Tacitus and Cassius Dio repeat variously elaborated rumours which held that Caligula, perhaps with Macro, was directly responsible for his death.{{sfn|Suet. ''Calig.''|loc=12}}{{sfn|Wiedemann|1996|p=221}}{{sfn|Tacitus|loc=[[wikisource:The Annals (Tacitus)/Book 12#53|XII.53]]}}{{sfn|Cassius Dio|loc=[https://penelope.uchicago.edu/Thayer/E/Roman/Texts/Cassius_Dio/58*.html lviii. 28]}} [[Philo]] and [[Josephus]], the latter a Romano-Jewish writer who served Vespasian a generation later, describe Tiberius' death as natural.{{sfn|Philo|loc=''On the Embassy'' [[s:On the Embassy to Gaius#IV|IV.25]]}}{{sfn|Josephus|loc=XIII.6.9}} On the same day, Caligula was hailed as emperor by members of the Praetorian guard at [[Misenum]]. His leadership of the ''domus Caesaris'' ("Caesar's household") as its sole heir and [[pater familias]] was ratified by the senate, who acclaimed him ''[[imperator]]'' two days after the death of Tiberius. Caligula entered Rome on 28 or 29 March, and with the consensus of "the three orders" (senate, equestrians and common citizens) the Senate conferred on him the "right and power to decide on all affairs".{{sfn|Winterling|2011|pp=50–51}}<ref name=":3">{{Cite book|title=[[Acta Fratrum Arvalium]]|year=1874|editor-last=Henzen|editor-first=Wilhelm|editor-link=Wilhelm Henzen|page=[https://books.google.com/books?id=a-9Wf6Yx9LgC&pg=PA59 63]}}</ref>

====''Princeps''====
In a single day, and with a single piece of legislation, the 25-year-old Caligula, previously a virtual unknown in Rome's political life, and with no military service, was thus granted the same trappings, authority and powers that Augustus had accumulated piecemeal, over a lifetime and sometimes reluctantly. Until his first formal meeting with the Senate, Caligula refrained from using the titles they had granted him. His studied deference must have gone some way to reassure the more astute that he should prove amenable to their guidance. Some must have resented the political manipulations that led to this extraordinary settlement. Caligula was now entitled to make, break or ignore any laws he chose.{{sfn|Barrett|2015|pp=77–82}} Augustus had shown, and Tiberius had failed to realise, that the roles of ''primus inter pares'' ("first among equals") and ''princeps legibus solutus'' ("a princeps not bound by the laws") required the exercise of personal responsibility, self-restraint, and above all, tact; as if the Senate still held the power they had voluntarily surrendered.{{sfn|Barrett| Yardley|2023|p=61}} In the words of scholar [[Anthony A. Barrett]], "Caligula would be restrained only by his own sense of discretion, which became in lamentably short supply as his reign progressed".{{sfnm|Gradel|2002|1pp=142–158|Winterling|2011|2pp=9–13, 51|Barrett|2015|3pp=79–80, 130–132}}

Caligula dutifully asked the Senate to approve divine honours for his predecessor but was turned down, in line with senatorial and popular opinion regarding the dead emperor's worth. Caligula did not push the issue; he had made the necessary gesture of filial respect.{{sfn|Barrett|2015|pp=72–74, 78–79, 82}} Tiberius' will named two heirs, Caligula and Gemellus, but the latter was still a minor, and could not hold any kind of office. The will was annulled with the standard justification that Tiberius must have been insane when he composed it, incapable of good judgment.{{sfn|Wiedemann|1996|p=221}}{{sfn|Cassius Dio|loc=LIX.1}} Although Tiberius' will had been legally set aside, Caligula honoured many of its terms, and in some cases, improved on them. Tiberius had provided each praetorian guardsman with a generous gratitude payment of 500 [[sesterce]]s. Caligula doubled this, and took credit for its payment as an act of personal generosity;{{sfn|Cassius Dio|loc=LIX.1}}{{sfn|Wiedemann|1996|p=222}} he also paid bonuses to the city troops and the army outside Italy.{{sfn|Cassius Dio|loc=LIX.1}}{{efn|Various coin issues suggest the payment of regular donations to the praetorians throughout Caligula's reign.{{sfn|Wiedemann|1996|p=222}} }} Every citizen in Rome was given 150 sesterces, and heads of households twice that amount. Building projects on the Palatine hill and elsewhere were also announced, which would have been the largest of these expenditures.{{sfn|Wiedemann|1996|p=222}}

Thanks to Macro's preparations on his behalf, Caligula's accession was a "brilliantly stage-managed affair".{{sfn|Barrett|2015|p=77}} The legions had already sworn loyalty to Caligula as their imperator. Now Caligula gave the miserly Tiberius a magnificent funeral at public expense, and a tearful eulogy,{{sfn|Wiedemann|1996|p=221}} and met with an ecstatic popular reception along the funeral route and in Rome itself. Among Caligula's first acts as emperor was the provision of public games on a grand scale. Philo describes Caligula in these early days as universally admired.{{sfn|Philo|loc=''On the Embassy'' [[s:On the Embassy to Gaius#II|II.10]]}} Suetonius writes that Caligula was loved by many, for being the beloved son of the popular Germanicus.{{sfn|Suet. ''Calig.''|loc=13}} Three months of public rejoicing ushered in the new reign.{{sfn|Suet. ''Calig.''|loc=14}} Philo describes the first seven months of Caligula's reign as a "[[Golden Age]]" of happiness and prosperity.{{sfn|Philo|loc=''On the Embassy'' [[s:On the Embassy to Gaius#II|II.12–13]]}} Josephus claims that in the first two years of his reign, Caligula's "high-minded... even-handed" rule earned him goodwill throughout the Empire.{{sfn|Barrett| Yardley|2023|p=99}}{{sfn|Josephus|loc=[[s:The Antiquities of the Jews/Book XVIII#Chapter 18|18.256]]}}

Caligula took up his first consulship on 1 July, two months after his succession. He accepted all titles and honours offered him except ''[[pater patriae]]'' ("father of the fatherland"), which had been conferred on Augustus. Caligula refused it, protesting his youth, until 21 September 37. He commemorated his own father, Germanicus, with portraits on coinage, adopted his name, and renamed the month of September after him. He granted his sisters and his grandmother [[Antonia Minor]] extraordinary privileges, normally reserved for the [[Vestal Virgin|Vestals]], and female priesthoods of the deified Augustus; their powers were entirely ceremonial, not executive, but their names were included in the standard formulas used in the senate house to invoke divine blessings on debates and proceedings, and the annual prayers for the safety of emperor and state. Caligula named his favourite sister, Drusilla, as heir to his ''[[imperium]]''. Oaths were sworn in the name of Caligula, and his entire family. One of his sesterces not only identifies each sister by name, but associates her with a particular imperial virtue; "security", "concord" or "fortune".{{sfn|Barrett|2015|pp=87–88}}<ref>{{Cite journal |last=Wood |first=Susan |date=1995 |title=Diva Drusilla Panthea and the sisters of Caligula |journal=American Journal of Archaeology |volume=99 |issue=3 |pages=436–439 |doi=10.2307/506945 |jstor=506945 |issn=0002-9114}}</ref> Caligula ordered that an image of his deceased mother, Agrippina, must accompany all festival processions. He made his uncle [[Claudius]] his consular colleague, tasked with siting statues of Caligula's two dead brothers, and occasionally standing in for Caligula at games, feasts and ceremonies. Claudius' own family found his limp and stammer "something of a public embarrassment"; he mismanaged the statue commission and his first consulship ended soon after, alongside Caligula's but his appointment elevated him from mere equestrian to senator, and eligible for consulship. Barrett and Yardley describe Claudius' consulship as an "astonishingly enlightened gesture" on Caligula's part, not one of Caligula's attempts to court popularity, as Suetonius would have it.{{sfn|Barrett| Yardley|2023|pp=76–77}}{{sfn|Suet. ''Calig.''|loc=15}}

Caligula made a public show of burning Tiberius' secret papers, which gave details of his infamous treason trials. They included accusations of villainy and betrayal against various senators, many of whom had willingly assisted in prosecutions of their own number to gain financial advantage, imperial favour, or to divert suspicion away from themselves; any expression of dissatisfaction with the emperor's rule or decisions could be taken as undermining the State, and lead to prosecution for ''maiestas'' (treason).{{sfn|Wiedemann|1996|p=219}} Caligula claimed – falsely, as it later turned out – that he had read none of these documents before burning them. He used a coin issue to advertise his claim that he had restored the security of the laws, which had suffered during Tiberius' prolonged absence from Rome; he reduced a backlog of court cases in Rome by adding more jurors and suspending the requirement that sentences be confirmed by imperial office.{{sfn|Wiedemann|1996|pp=222–223}}

Stressing his descent from Augustus, Caligula retrieved the remains of his mother and brothers from their places of exile for interment in the Mausoleum of Augustus.{{sfn|Wiedemann|1996|p=223}}{{sfn|Cassius Dio|loc=LIX.3}} Caligula began work on a temple to [[Livia]], widow of Augustus; she held the honorific title of [[Augusta (title)|Augusta]] while still living, and when she died was eventually made a ''diva'' (goddess) of the Roman state under Claudius. The temple had been vowed in her lifetime, but not constructed.{{sfn|Wiedemann|1996|p=223}}

==== Illness and recovery ====
Between approximately mid-October and mid-November 37, Caligula fell seriously ill through unknown causes and hovered for a month or so between life and death. Rome's public places filled with citizens who implored the gods for his recovery, some even offering their own lives in exchange. By late October, their emperor had recovered, and embarked on what might have been a purge of suspected opponents or conspirators.{{sfn|Barrett|2015|pp=108, 334}} Caligula's relations with his senate had been congenial but were now sullied by the forced suicide, for reasons unknown, of the eminent senator Silanus, formerly Caligula's father-in-law. Gemellus, Caligula's adopted son and heir, now 18 years old and legally adult, was also disposed of.{{sfn|Barrett|2015|pp=307–309}} Suetonius offers several versions of Gemellus' death. In one, Gemellus was given the adult ''toga virilis'' then charged with having taken an antidote, "implicitly accusing Caligula of wanting to poison him", and forced to kill himself. Several months later, in early 38, Caligula forced suicide on his Praetorian Prefect, Macro, without whose help and protection he would not have survived, let alone gained the throne as sole ruler.{{sfn|Cassius Dio|loc=LIX.10}}{{sfn|Barrett|2015|pp=47–48, 93}} Any link between the deaths is speculative, but it is possible that Silanus had conspired to make Gemellus emperor, should Caligula fail to recover; and Caligula might simply have tired of Macro's control and influence.{{sfn|Barrett|Yardley|2023|pp=85–86, 88–91}}

In 38, Caligula nominated [[Marcus Aemilius Lepidus (executed by Caligula)|Marcus Aemilius Lepidus]] as his heir, and married him to his beloved sister Drusilla, but on 19 June that year, Drusilla died. She was deified and renamed Panthea ("All Goddesses"); the first mortal woman in Roman history to be made a ''diva'' (goddess of state). Caligula, bereft, declared a period of compulsory, universal mourning. Drusilla's death is one of several events approximate to the time of Caligula's illness, besides the death of Antonia and any unreported effects of the illness itself, thought by some to contribute to a fundamental change in Caligula's attitudes. Purges so early in Caligula's reign suggest to Weidemann that "the new emperor had learnt a great deal from Tiberius" and "that attempts to divide his reign into a 'good' beginning followed by unremitting atrocities [...] are misplaced".{{sfn|Wiedemann|1996|p=223. "It is useless to date the turning-point to before the death of Antonia (two months after his accession), an illness in the autumn... which is supposed to have affected his brain, or the death of his sister Drusilla"}}

===Public profile===
Caligula shared many of the popular passions and enthusiasms of the lower classes and young aristocrats: public spectacles, particularly gladiator contests, chariot and horse racing, the theatre and gambling, but all on a scale which the nobility could not match. He trained with professional gladiators and staged exceptionally lavish gladiator games, being granted exemption by the senate from the [[sumptuary laws]] that limited the number of gladiators to be kept in Rome. He was openly and vocally partisan in his uninhibited support or disapproval of particular charioteers, racing teams, gladiators and actors, shouting encouragement or scorn, sometimes singing along with paid performers or declaiming the actors' lines, and generally behaving as "one of the crowd". In gladiator contests, he supported the ''[[Parmularius (gladiator)|parmularius]]'' type, who fought using small, round shields. In chariot races, he supported the [[Chariot Racing#Factions|Greens]], and personally drove his favourite racehorse, [[Incitatus]] ("Speedy") as a member of the Green faction. Most of Rome's aristocracy would have found this an unprecedented, unacceptable indignity for any of their number, let alone their emperor.{{sfn|Barrett|2015|pp=65–67}}{{sfn|Winterling|2011|pp=79–81}}{{sfn|Cassius Dio|loc=LIX.5.4}}

Caligula showed little respect for distinctions of rank, status or privilege among the senate, whose members Tiberius had once described as "men ready to be slaves". Among those whom Caligula recalled from exile were actors and other public performers who had somehow caused Tiberius offence.{{sfn|Wiedemann|1996|p=222}}{{sfn|Suet. ''Calig.''|loc=15}} Caligula seems to have built a loyal following among his own loyal [[Ancient Roman freedmen|freedmen]], citizen-commoners, disreputable public performers on whom he lavished money and other gifts; and the lower nobility (equestrians) rather than the senators and nobles whom he clearly and openly mistrusted, despised and humiliated for their insincere simulations of loyalty.{{sfn|Barrett|2015|pp=116–118, 130–132, 297–298}} Dio notes, with approval, that Caligula allowed some equestrians senatorial honours, anticipating their later promotion to senator based on their personal merits.{{sfn|Cassius Dio|loc=LIX.9–10}} To reverse declining membership of the equestrian order, Caligula recruited new, wealthy members empire-wide, and scrupulously vetted the order's membership lists for signs of dishonesty or scandal. He seems to have ignored trivial misdemeanours, and would have anticipated the creation of "new men" (''[[novus homo|novi homines]]''), first of their families to serve as senators. They would owe him a debt of gratitude and loyalty for their advancement.{{sfn|Barrett|2015|pp=304–305}}

Barrett describes some of the supposed equestrian offences punished by Caligula as "decidedly trivial", and their punishments as sensationalist. Dio claims that Caligula had more than 26 equestrians executed in a circus "fracas"; in Suetonius' biography "more than 20" lives were lost in what is almost certainly the same event, described as a violent but accidental crush.{{sfn|Barrett|2015|pp=304–305}} Some sources claim that Caligula forced equestrians and senators to fight in the arena as gladiators.{{sfn|Suet. ''Calig.''|loc=56}}{{sfn|Tacitus|loc=16.17}}{{sfn|Josephus|loc=[[s:The Antiquities of the Jews/Book XIX#Chapter 1|XIX.1.2]]}} Condemnation to the gladiator arena as a combatant was a standard punishment, doubling as public entertainment, for non-citizens found guilty of certain offences. Laws of AD 19 by Augustus and Tiberius banned voluntary participation of the elite in any public spectacles, but the ban was never particularly effective, and was broadly ignored in Caligula's reign. During Caligula's illness two citizens, one of whom was an equestrian, offered to fight as gladiators if only the gods would spare the emperor's life. The offers were insincere, intended to flatter and invite reward. When Caligula recovered, he insisted that they be taken at face value, to avoid accusations of perjury: "cynical, but not without wit of a kind".{{sfn|Winterling|2011|pp=70–72}}

=== Public reform and finance ===
[[File:RIC 0039.jpg|thumb|right|[[Quadrans]] celebrating the abolition of a tax in AD&nbsp;38 by Caligula. The obverse of the coin contains a picture of a [[Pileus (hat)|Pileus]] which symbolizes the liberation of the people from the tax burden. Caption: {{Smallcaps|{{abbr|c|GAIUS}} caesar divi {{abbr|avg|AUGUSTUS}} {{abbr|pron|PRONEPOS}} {{abbr|avg|AUGUSTUS (i.e. Gaius Caesar, great-grandson of the Divine Augustus)}} / {{abbr|pon m|PONTIFEX MAXIMUS}}, {{abbr|pp|PATER PATRIAE}} {{abbr|cos des|CONSUL DESIGNATUS}} {{abbr|rcc|RES CIVIUM CONSERVATAE (i.e. the interests of citizens have been preserved)}}}}.]]
[[File:Caligula - Münzkabinett, Berlin - 5481108.jpg|thumb|The ''adlocutio cohortium'' of Caligula on a coin, giving a speech to the army]]

In 38, Caligula lifted censorship, and published accounts of public funds and expenditure. Suetonius congratulates this as the first such act by any emperor.{{sfn|Barrett|2015|p=297}}{{efn|In fact, Tiberius had published the imperial accounts once, and Augustus had done so twice. Caligula's publication was thought a highly creditable act, but he did not repeat it.{{sfn|Barrett|2015|p=297}}}} Very soon after his succession, he restored the right of the popular assembly ([[comitia]]) to elect magistrates on behalf of the common citizenry, a right that had been taken over by the Senate under Tiberius and Augustus. The [[aedile]]s, elected officials who managed public games and festivals, and maintained the fabric of roads and shrines, would now have incentive to spend their own money on lavish, high-profile spectacles and other ''[[Munera (ancient Rome)|munera]]'' (gifts to the state or people), to win the popular vote.{{sfn|Wiedemann|1996|p=222}} Dio writes that this, "though delighting the rabble, grieved the sensible, who stopped to reflect, that if the offices should fall once more into the hands of the many... many disasters would result".{{sfn|Cassius Dio|loc=LIX.9–10}} When the Senate outright refused to accept this, Caligula restored control of elections to them. Either way, the emperor ultimately chose which candidates stood for election, and which were elected. Caligula was quite capable of recognising his own plans and decisions as flawed, and abandoning, revising or reversing them when faced with opposition.{{sfn|Barrett|2015|p=312}} He was open to good advice, but could just as easily take its offering as an insult to his youth or understanding – Philo quotes his warning "Who dares teach me?" Caligula abandoned his plan to convert the Temple of Jerusalem to a temple of the Imperial cult, with a statue of himself as Zeus, when warned that the plan would arouse extreme protests, and injure the local economy.{{sfn|Barrett|2015|pp=215, 312}}{{efn|Jewish grain producers had threatened to fire their fields if Caligula's plan went ahead. This would have caused a local grain famine during Caligula's planned visit to Alexandria.{{citation needed |date=August 2024}} }} He gave funds where they were needed; he helped those who lost property in fires, and abolished a deeply unpopular tax on sales, but whether his extravagant gifts to favourites during his earliest reign – be they actors, charioteers or other public performers – drew on his personal wealth or state coffers is not known. Personal generosity and magnanimity, coupled with discretion and responsibility, were expected of the ruling elite, and the emperor in particular.{{sfn|Cassius Dio|loc=LIX.9–10}}{{sfn|Suet. ''Calig.''|loc=16.2}} At some time, Caligula ruled that bequests to office-holders remain property of the office, not of the office-holder.{{sfn|Barrett|2015|pp=297–98, 301–302}}{{sfn|Cassius Dio|loc=LIX.9–10}}{{sfn|Suet. ''Calig.''|loc=16.2}}

==== Tax and treasury ====
Suetonius claims that Caligula squandered 2.7&nbsp;billion [[Sestertius|sesterces]] in his first year{{sfn|Suet. ''Calig.''|loc=37}} and addressed the consequent treasury deficit by confiscating the estates of wealthy individuals, after false accusations, fines or outright seizure, even the death penalty, as a means of raising money. This seems to have started in earnest around the time of Caligula's confrontation with the senate (in early 39).{{sfn|Suet. ''Calig.''|loc=38}} Suetonius's retrospective balance sheet overlooks what would have been owed to Caligula, personally and in his capacity as emperor, on Tiberius' death, and the release of the former emperor's hoarded wealth into the economy at large. Caligula's inheritance included the deceased empress [[Livia]]'s vast bequest, which Caligula distributed among its nominated public, private and religious beneficiaries. Barrett in ''Caligula: The Abuse of Power'' asserts that this "massive cash injection would have given the Roman economy a tremendous boost".{{sfn|Barrett|2015|p=298}}

Dio remarks the beginnings of a financial crisis in 39, and connects it to the cost of Caligula's extravagant bridge-building project at Baiae.{{sfn|Cassius Dio|loc=LIX.10}} Suetonius has presumably the same financial crisis starting in 38; he does not mention a bridge but lists a broad range of Caligula's extravagances, said to have exhausted the state treasury.{{sfn|Suet. ''Calig.''|loc=37}}

To Wilkinson, Caligula's uninterrupted use of precious metals in coin issues does not suggest a bankrupt treasury, though there must have been a blurring of boundaries between Caligula's personal wealth, and his income as head of state.{{sfn|Wilkinson|2004|p=10}} Caligula's immediate successor, [[Claudius]], abolished taxes, embarked on various costly building projects and donated 15,000 sesterces to each [[Praetorian Guard]] in 41{{sfn|Tacitus|loc=[[wikisource:The Annals (Tacitus)/Book 12#53|XII.53]]}}{{sfn|Suet. ''Claud.''|loc=10}} as his own reign began, which suggests that Caligula had left him a solvent treasury.{{sfnm|Alston|1998|1p=82|Salmon|1987|2p=153}}

In the long term, the occasional windfall aside, Caligula's spending exceeded his income. Fund-raising through taxation became a major preoccupation. Provincial citizens were liable for direct payment of taxes used to fund the military, a payment from which Italians were exempt. Caligula abolished some taxes, including the deeply unpopular sales tax, but he introduced an unprecedented range of new ones, and rather than employ professional tax farmers ([[publicani]]) in their collection, he made this a duty of the notoriously forceful Praetorian Guard. Dio and Suetonius describe these taxes as "shameful": some were remarkably petty. Caligula taxed "taverns, artisans, slaves and the hiring of slaves", edibles sold in the city, litigation anywhere in the Empire, weddings or marriages, the wages of porters "or perhaps couriers", and most infamously, a tax on prostitutes (active, retired or married) or their pimps, liable for "a sum equivalent to a single transaction". Citizens of provincial Italy lost their previous tax exemptions. Most individual tax bills were fairly small but cumulative; over Caligula's brief reign, taxes were doubled overall. Even then, the revenue was nowhere near enough, and the imposition was deeply resented by Rome's commoners. Josephus claims that this led to riotous protests at the Circus. Barrett remarks that stories of consequent "mass executions" there by the military should "almost certainly" be dismissed as "standard exaggeration".{{sfn|Suet. ''Calig.''|loc=12}}{{sfn|Barrett|2015|pp=298–301}}{{sfn|Josephus|loc=[[s:The Antiquities of the Jews/Book XIX#Chapter 19|19.28]]}}

Property or money left to Tiberius as emperor but not collected on his death would have passed to Caligula as office-holder. Roman inheritance law recognised a legator's obligation to provide for his family; Caligula seems to have considered his fatherly duties to the state entitled him to a share of every will from pious subjects. The army was not exempt; centurions who left nothing or too little to the emperor could be judged guilty of ingratitude, and have their wills set aside. Centurions who had acquired property by plunder were forced to turn over their spoils to the state.{{sfn|Cassius Dio|loc=LIX.15}}{{sfn|Barrett|2015|pp=224, 301}}

Stories of a brothel in the Imperial palace, staffed by Roman aristocrats, matrons and their children, are taken literally by Suetonius and Dio; McGinn believes they could be based on a single incident, extended to an institution in the telling.<ref>{{Cite journal |last=McGinn |first=Thomas A J |date=1998 |title=Caligula's Brothel on the Palatine |url=https://muse.jhu.edu/pub/50/article/651730/summary |journal=Echos du Monde Classique: Classical News and Views |volume=42 |issue=1 |pages=95–107 |issn=1913-5416}}</ref>{{page needed |date=August 2024}} Similar allegations would be made in the future against [[Commodus]] and [[Elagabalus]].{{sfn|Barrett|2015|pp=299–302}} Winterling, citing Dio 59.28.9, traces the outline of the story to Cassius Dio's account for AD 40, and his allegation that the noble tenants of newly built suites of rooms at the palace were compelled to pay exorbitant rents for the privilege of living so close to Caligula, and under the protection of the praetorians. No brothel is mentioned in this account.{{sfn|Winterling|2011|pp=140–143}} Suetonius appears to reverse the traditional aristocratic client-patron ceremonies of mutual obligation, and have Caligula accepting payments for maintenance from his loyal consular "friends" at morning salutations, evening banquets, and bequest announcements. The sheer numbers of "friends" involved meant that meticulous records were kept of who had paid, how much, and who still owed. His agents would then visit the very same consuls who had been involved in conspiracies against him, rail against the Senate's treachery ''en masse'' but ask for "gifts" from individuals to express their loyal friendship in return. A refusal was unthinkable. Winterling describes the families who occupied these rooms as hostage, under the supervision of the Praetorians; some paid up willingly, some reluctantly, but all paid. Caligula made loans available at high interest to those who lacked the necessary funds, to complete the humiliation of Rome's elite, especially the old Republican families.{{sfn|Winterling|2011|pp=140–143}}

Despite his biographers' attempts to ridicule Caligula's taxes, many were continued after his death. The military remained responsible for all tax collection, and the tax on prostitution continued up to the reign of [[Severus Alexander]]. Caligula's ruling that bequests made to any reigning emperor became property of his office, not himself as a private individual, was made constitutional under [[Antoninus Pius]].{{sfn|Barrett|2015|pp=301–302}}

==== Coinage ====
Caligula did not change the structure of the monetary system established by Augustus and continued by Tiberius, but the contents of his coinage differed from theirs.{{sfn|Mattingly|Sydenham|Sutherland|1923–1984|p=102}} The location of the imperial mint for the coins of precious metals (gold and silver) is a matter of debate among ancient numismatists. It seems that Caligula initially produced his precious coins from [[Lugdunum]] (now [[Lyon]], France), like his predecessors, then moved the mint to Rome in 37–38, although it is possible that this move occurred later, under Nero.{{sfn|Mattingly|Sydenham|Sutherland|1923–1984|pp=102, 103}} His [[base metal]] coinage was struck in Rome.{{sfn|Mattingly|Sydenham|Sutherland|1923–1984|pp=103–106}}

Unlike Tiberius, whose coins remained almost unchanged throughout his reign, Caligula used a variety of types, mostly featuring [[Roman imperial cult|Divus Augustus]], as well as his parents Germanicus and Agrippina, his dead brothers [[Nero Julius Caesar|Nero]] and [[Drusus Caesar|Drusus]], and his three sisters [[Agrippina the Younger|Agrippina]], [[Julia Drusilla|Drusilla]], and [[Julia Livilla|Livilla]]. The reason for the extensive emphasis on his relatives was to highlight Caligula's double claim to the Principate, from both the Julian and Claudian sides of the dynasty, and to call for the unity of the family.{{sfn|Mattingly|Sydenham|Sutherland|1923–1984|pp=104–105}} The sesterce with his three sisters was discontinued after 39, due to Caligula's suspicion regarding their loyalty. He also made a sesterce celebrating the Praetorian cohorts as a mean to give them the bequest of Tiberius at the beginning of his reign. Caligula minted a [[quadrans]], a small bronze coin, to mark the abolition of the ''ducentesima'', a 0.5% tax on sales.{{sfn|Mattingly|Sydenham|Sutherland|1923–1984|p=105}} The output of the precious metal mints was small and his sesterces were mostly made in limited quantities, which make his coins now very rare. This rarity cannot be attributed to Caligula's alleged ''damnatio memoriae'' reported by Dio, as removing his coins from circulation would have been impossible; besides, [[Mark Antony]]'s coins continued to circulate for two centuries after his death.{{sfn|Mattingly|Sydenham|Sutherland|1923–1984|pp=106–107}} Caligula's common coins are base metal types with [[Vesta (mythology)|Vesta]], Germanicus, and Agrippina the Elder, and the most common is an [[As (Roman coin)|as]] with his grandfather [[Marcus Vipsanius Agrippa|Agrippa]].{{sfn|Mattingly|Sydenham|Sutherland|1923–1984|p=105}} Finally, Caligula kept open the mint at [[Caesarea (Mazaca)|Caesarea]] in [[Cappadocia (Roman province)|Cappadocia]], which had been created by Tiberius, in order to pay military expenses in the province with silver [[Ancient drachma|drachmae]].{{sfn|Mattingly|Sydenham|Sutherland|1923–1984|p=107}}

Numismatists [[Harold Mattingly]] and [[Edward A. Sydenham|Edward Sydenham]] consider that the artistic style of Caligula's coins is below those of Tiberius and Claudius; they especially criticize the portraits, which are too hard and lack details.{{sfn|Mattingly|Sydenham|Sutherland|1923–1984|p=107}}

=== Construction ===
{{See also|Caligula's Giant Ship|Nemi ships}}
Caligula had a fondness for grandiose, costly building projects, many of which were intended to benefit or entertain the general population but are described in Roman sources as wasteful. In the city of Rome, he completed the [[Temple of Divus Augustus|temple of Augustus]] and the reconstruction of the [[theatre of Pompey]]. He is said to have built a bridge between the temple of Castor and Pollux and the Capitol.{{efn|By a modern calculation, it would have spanned a distance of 250.m, and risen to 35 m. above ground level to clear the intervening temple of Augustus.{{citation needed |date=August 2024}} }} Barrett (2015) believes that this bridge existed only in Suetonius' account, and should perhaps be dismissed as a fantasy, with possible origins in some jocular remark by Caligula.{{sfn|Barrett|2015|pp=197, 238–239}}{{sfn|Suet. ''Calig.''|loc=22}}

Caligula began an [[Amphitheater of Caligula|amphitheatre]] beside the [[Saepta Julia]]; he cleared the latter space for use as an arena, and filled it with water for a single [[naumachia]] (a sham naval battle fought as entertainment).{{sfn|Cassius Dio|loc=LIX.10}} He supervised the extension and rebuilding of the imperial palace to include a gallery for his art collection. Philo and his party were given a tour of the gallery during their diplomatic visit. Barrett (2015) considers Philo's description of Caligula as a "would-be connoisseur and aesthete" as "probably not very wide of the mark."{{sfn|Suet. ''Calig.''|loc=21, 22}}{{sfn|Barrett|2015|pp=223–226}} To help meet Rome's burgeoning demand for fresh water, he began the construction of aqueducts [[Aqua Claudia]] and [[Anio Novus]], which [[Pliny the Elder]] considered to be engineering marvels.{{sfn|Suet. ''Calig.''|loc=20, 21}}{{sfn|Pliny the Elder|loc=[[s:Natural History (Rackham, Jones, & Eichholz)/Book 36|XXXVI,122]]}}{{sfn|Barrett|2015|pp=225–226}} He built a large racetrack, now known as the [[Circus of Nero|Circus of Gaius and Nero]]. In its central spine he incorporated an Egyptian obelisk, now known as the [[Vatican obelisk]], which he had brought by sea on a gigantic, purpose-built ship, which used 120,000 modi of lentils as ballast.{{efn|The ship proved impractical to use in the grain trade and would eventually be submerged, filled with concrete to form a harbour mole and lighthouse foundation, as part of Claudius' expansion of Rome's harbour at Ostia.{{citation needed |date=August 2024}} }}{{sfn|Pliny the Elder|loc=[[s:Natural History (Rackham, Jones, & Eichholz)/Book 16|XVI.76]]}}{{sfn|Barrett|2015|p=224}}

At [[Syracuse, Sicily|Syracuse]], he repaired the city walls and temples.{{sfn|Suet. ''Calig.''|loc=21}} He pushed to keep roads in good condition throughout the empire, and extended the existing network: to this end, Caligula investigated the financial affairs of current and past highway commissioners. Those guilty of negligence, embezzlement or misuse of funds were forced to repay what they had dishonestly used for other purposes, or fulfil their commissions at their own expense.{{sfn|Suet. ''Calig.''|loc=37}}{{sfn|Cassius Dio|loc=LIX.15}}{{sfn|Barrett|2015|p=224}} Caligula planned to rebuild the palace of [[Polycrates]] at Samos, to finish the temple of Didymaean Apollo at [[Ephesus]], and house his own cult and image there: and to found a city high up in the [[Alps]]. He intended to dig a canal through the [[Isthmus of Corinth]] in Greece and sent a chief centurion to survey the site. None of these plans came to fruition.{{sfn|Suet. ''Calig.''|loc=21}}{{sfn|Barrett|2015|pp=225–226, 246 n. 85}}

=== Treason trials ===
In the course of 39, Caligula's increasingly tense relationship with his Senate deteriorated into outright hostility and confrontation.{{sfn|Cassius Dio|loc=LIX.16}}{{sfn|Suet. ''Calig.''|loc=30}} This is one of Dio's more confusing accounts, involving conspiracies, denunciations and trials for treason (''maiestas''), following Caligula's launch of invective at the entire senate, reviewing and condemning their current and past behaviour. He accused them of servility, treachery and hypocrisy in voting honours to Tiberius and Sejanus while they lived, and rescinding those honours once their recipients were safely dead. He declared that it would be folly to seek the love or approval of such men: they hated him, and wanted him dead, so it would be better that they should fear him. Caligula's diatribes exposed the idealised ''princeps'' or First Senator as illusion and imposture. When the senate returned next day, they seemed to confirm his suspicions, and voted him a special guard of armed pretorians to protect him and guard his statues. Apparently seeking to please him and assure his safety, the Senate proposed that his senatorial chair be raised "on a high platform even in the very Senate house".<ref>Cassius Dio, (in [[John Xiphilinus (historian)|John Xiphilinus]]' epitome), 59, 26, 3.</ref>{{sfn|Barrett|2015|pp=251–252}} They offered a thanksgiving to Caligula, as to a monarch, expressing gratitude for allowing them to live when others had died.{{sfn|Winterling|2011|pp=98–100}} Winterling suggests that Caligula's three subsequent consulships, sworn at the [[Rostra]], were vain attempts to make amends, public statements of respect for the senators as his equals.{{sfn|Winterling|2011|pp=90–103}} Barrett perceives these later consulships as symbolic of Caligula's continued intention to dominate the senate and the state;{{sfn|Barrett|2015|p=304}}{{efn|Caligula stepped down soon after each award of consulship, to allow a [[suffect]] consul to replace him. In effect, this made consulship a gift of the emperor.{{citation needed |date=August 2024}} }} Barrett describes the change in Caligula's rule as a gradual unravelling, a "descent into serious mismanagement and impenetrable mistrust" – and, latterly, into "arbitrary terror"; but Dio's claim that in fact, "there was nothing but slaughter" is undermined by evidence that most senators managed to survive Caligula's reign with their persons and fortunes intact.{{sfn|Barrett|2015|pp=131, 308}}

Caligula had not, after all, destroyed Tiberius' records of treason trials. He reviewed them and decided that numerous senators discharged from Tiberius' court hearings seemed to have been guilty of conspiracy all along, against emperor and state – the worst form of ''[[Law of majestas|maiestas]]'' (treason). Tiberius' treason trials had encouraged professional ''[[delatores]]'' (informers), who were loathed by the populace, but many of the accused had testified against each other, and against Caligula's own family, even to the point of initiating the prosecutions themselves. If they had acted against Caligula's family, they might act against Caligula himself. New investigations were launched; Dio names five once-trusted, consular senators tried for ''maiestas'', but his allegation that senators or others were put to death in "great numbers" is unsupported.{{sfn|Suet. ''Calig.''|loc=30}}{{sfn|Cassius Dio|loc=LIX.16.2–4}}{{sfn|Winterling|2011|pp=90–95, 96–101}} Two of the five prospered under his rule, and beyond.{{sfn|Barrett|2015|p=309}} Caligula preferred to publicly humiliate his enemies in the senate, especially those of ancient families, by stripping them of their inherited honours, dignities and titles.{{sfn|Barrett|2015|p=310}}{{sfn|Suet. ''Calig.''|loc=26}} In early September, he dismissed the two suffect consuls, citing their inadequate, low-key celebration of his birthday (31 August) and excessive attention to the anniversary of [[Actium]] (2 September). This was the last battle in a damaging civil war between two of Caligula's close ancestors, which he found no cause for celebration. One of the dismissed consuls killed himself: Caligula may have suspected him of conspiracy.{{sfn|Barrett|2015|p=135}}

==== Incitatus ====
Suetonius and Dio outline Caligula's supposed proposal to promote his favourite racehorse, [[Incitatus]] ("Swift"), to [[consul]], and later, a priest of his own cult.{{sfn|Winterling|2011|pp=103–104}}{{sfn|Cassius Dio|loc=LIX.28}} This could have been an extended joke, created by Caligula himself in mockery of the senate. A persistent, popular belief that Caligula actually promoted his horse to consul has become "a byword for the promotion of incompetents", especially in political life.{{sfn|Barrett|2015|pp=288–289}} It may have been one of Caligula's many oblique, malicious or darkly humorous insults, mostly directed at the senatorial class, but also against himself and his family. Winterling sees it as an insult to the consulars themselves. An aristocrat's highest ambition, the consulship, could be laid open to ruinous competition and at the same time, to ridicule. David Woods believes it unlikely that Caligula meant to insult the post of consul, as he had held it himself. Suetonius, possibly failing to get the joke, presents it as further proof of Caligula's insanity, adding circumstantial details more usually expected of the senatorial nobility, including palaces, servants and golden goblets, and invitations to banquets.{{sfn|Winterling|2011|pp=103–104}}<ref>{{cite journal|last1=Woods|first1=David|title=Caligula, Incitatus, and the Consulship|journal=The Classical Quarterly|year=2014|volume=64|issue=2|pages=772–777|doi=10.1017/S0009838814000470|s2cid=170216093|issn=0009-8388}}</ref>

==== Bridge at Baiae ====
In 39 or 40, by Suetonius' reckoning, Caligula ordered a temporary [[Pontoon bridge|floating bridge]] to be built using a double line of ships as [[Pontoon (boat)|pontoons]], earth-paved and stretching for over two miles from the resort of [[Baiae]], near [[Naples]], to the neighbouring port of [[Puteoli]], with resting places between.{{sfn|Suet. ''Calig.''|loc=19}}{{sfn|Cassius Dio|loc=LIX.17}} Some ships were built on site but grain ships were also requisitioned, brought to site, secured and temporarily resurfaced. Any practical purpose for the bridge is unclear; Winterling believes that it might have been intended to mark Caligula's attempted invasion of Britain.<ref>{{cite journal|last1=Wardle|first1=David|title=Caligula's Bridge of Boats – AD 39 or 40?|journal=Historia: Zeitschrift für Alte Geschichte|year=2007|volume=56|issue=1|pages=118–120|jstor=25598379}}</ref>{{sfn|Winterling|2011|pp=126–129ff, 169}} A two-day ceremonial was performed, with offerings to the sea-god [[Neptune (mythology)|Neptune]] and [[Invidia]] (Envy), and a satisfactory result, in that the sea remained completely calm. The bridge was said to rival the Persian king [[Xerxes' pontoon bridges|Xerxes' pontoon bridge]] across the [[Hellespont]].{{sfn|Suet. ''Calig.''|loc=19}}{{sfn|Cassius Dio|loc=LIX.17}}{{sfn|Barrett|2015|pp=240–242}}

For the opening ceremony, Caligula donned the supposed breastplate of [[Alexander the Great#Post-death events|Alexander the Great]], and rode his favourite horse, [[Incitatus]], across the bridge,{{sfn|Suet. ''Calig.''|loc=19}} perhaps defying a prediction, attributed by Suetonius to Tiberius' soothsayer [[Thrasyllus of Mendes]], that Caligula had "no more chance of becoming emperor than of riding a horse across the Bay of Baiae".{{sfn|Suet. ''Calig.''|loc=19}} On the second day, he rode the bridge from end to end several times "at full tilt", accompanied by the soldiery, famous nobles and hostages. [[Seneca the Younger|Seneca]] and Dio claim that grain imports were dangerously depleted by Caligula's re-purposing of Rome's grain ships as pontoons.{{sfn|Seneca the Younger|loc=[[s:On the shortness of life|''On the Shortness of Life'']] XVIII.5}} Barrett finds these accusations absurd; if the bridge was finished in 39, that was far too early to have had any effect on the annual grain supply, and "a genuine grain crisis was simply blamed on the most outlandish episode at hand." Dio places this episode soon after Caligula's furious denunciation of the Senate; Barrett speculates that Caligula may have intended the whole event as an object lesson on how completely he was in charge: it may also provide "the most striking example of his wasteful extravagance"; its pointlessness might have been the whole point.{{sfn|Barrett|2015|pp=240–242, 132}}

===Provinces===
==== Judaea and Egypt ====
Caligula's reign saw an increase of tensions between Jews native to their homeland of [[Judaea (Roman province)|Judea]], Jews of the diaspora, and ethnic Greeks. Greeks and Jews had settled throughout the Roman Empire and Judaea was ruled as a Roman client kingdom. Jews and Greeks had settled in Egypt following its conquest by Macedonian Greeks, and remained there after its conquest by Rome.{{sfn|Barrett|2015|p=207}} While the Alexandrian Greeks held citizen status, Alexandrian Jews were classified as mere settlers, with no statutory or citizen rights other than those granted them by their Roman governors. The Greeks feared that official recognition of Jews as citizens would undermine their own status and privilege.{{sfn|Barrett|2015|pp=207–209}}

Caligula had replaced the prefect of Egypt, [[Aulus Avilius Flaccus]], with [[Herod Agrippa]], who was governor of [[Batanaea]] and [[Trachonitis]], and was a personal friend.{{sfn|Josephus|loc=[[s:The Antiquities of the Jews/Book XVIII#Chapter 6|XVIII.6.10]]}}{{sfn|Philo|loc=''Flaccus'' [[s:Flaccus#V|V.25]]}} Flaccus had conspired against Caligula's mother and had connections with Egyptian separatists.{{sfn|Philo|loc=''Flaccus'' III.8, IV.21}} In 38, Caligula sent Agrippa to Alexandria unannounced to check on Flaccus.{{sfn|Philo|loc=''Flaccus'' V.26–28}} According to Philo, the visit was met with jeers and mockery from the Greek population who saw Agrippa as a gimcrack "king of the Jews.”{{sfn|Philo|loc=''Flaccus'' [[s:Flaccus#VI|VI.43]]}} In Philo's account, a mob of Greeks broke into synagogues to erect statues and shrines of Caligula, against Jewish religious law. Flaccus responded by declaring the Jews "foreigners and aliens", and expelled them from all but one of Alexandria's five districts, where they lived under dreadful conditions. Philo gives an account of various atrocities inflicted on Alexandria's Jews within and around this ghetto by the city's Greek population.{{sfn|Philo|loc=''Flaccus'' [[s:Flaccus#VII|VII.45]]}} Caligula held Flaccus responsible for the disturbances, exiled him, and eventually executed him.{{sfn|Philo|loc=''Flaccus'' [[s:Flaccus#XXI|XXI.185]]}}{{sfn|Barrett|2015|pp=207–212}}

In 39, Agrippa accused his uncle [[Herod Antipas]], the [[Tetrarchy (Judea)|tetrarch]] of [[Galilee]] and [[Perea (Holy Land)|Perea]], of planning a rebellion against Roman rule with the help of [[Parthia]]. Herod Antipas confessed, Caligula exiled him, and Agrippa was rewarded with his territories.{{sfn|Josephus|loc=XVIII.7.2}} Riots again erupted in Alexandria in 40 between Jews and Greeks, when Jews who refused to venerate the emperor as a god were accused of dishonouring him.{{sfn|Josephus|loc=XVIII.8.1}} In the Judaean city of [[Yavne|Jamnia]], resident Greeks built a shoddy, sub-standard altar to the [[Imperial cult of ancient Rome|Imperial cult]], intending to provoke a reaction from the Jews; they immediately tore it down. This was interpreted as an act of rebellion.{{sfn|Philo|loc=''On the Embassy'' [[s:On the Embassy to Gaius#XXX|XXX.201]]}} In response, Caligula ordered the erection of a statue of himself in the Jewish [[Temple of Jerusalem]],{{sfn|Philo|loc=''On the Embassy'' [[s:On the Embassy to Gaius#XXX|XXX.203]]}}<ref name=":02">{{Cite book |last=Millar |first=Fergus |title=The Roman Near East: 31 BC–AD 337 |publisher=Harvard University Press |year=1995 |isbn=978-0-674-77886-3 |edition= |location=Cambridge, Massachusetts |pages=58 |chapter= |quote=}}</ref> a political, rather than a religious act for Rome, but a blasphemy for the Jews, and in conflict with Jewish monotheism. In this context, Philo wrote that Caligula "regarded the Jews with most especial suspicion, as if they were the only persons who cherished wishes opposed to his".{{sfn|Philo|loc=''On the Embassy'' [[s:On the Embassy to Gaius#XVI|XVI.115]]}}

In May of 40, Philo accompanied a deputation of Alexandrian Jews and Greeks to Caligula, and a second deputation after 31 August that year, during the worst of the Alexandrian riots. Neither of these encounters proved decisive. Both gave Caligula ample opportunity for casual, friendly banter, which seems to have included humiliating levity, always at the Jewish delegation's expense; but he made no claims of divinity, either in his dress nor his speech, merely asking at the second encounter, more or less rhetorically, why Jews found his veneration so difficult. Philo and Josephus each saw Caligula's behaviour as driven by his claims to divinity, which for a Jew would have virtually defined him as fundamentally insane, despite appearances otherwise.{{sfn|Winterling|2011|pp=156–159}}

The ethnically Greek population of Alexandria had already made their loyalty to the new emperor clear, with displays of his image as focus for his cult.{{sfn|Winterling|2011|pp=156–157}} The destruction of the altar at Jamlia and, presumably, removal of "idolatrous" images placed in synagogues by Greek citizens, might have been intended as an expression of Jewish religious fervour, rather than a response aimed at one tyrant's offensive claims of personal godhood. Philo seems to have loathed Caligula from the start, but his belief that Caligula hated the Jews and was preparing their destruction has no basis in evidence. To place Caligula's statue in Temple precincts, showing him dressed as Jupiter, would have been consistent with the Empire-wide religious phenomenon known as [[Imperial cult]], from whose full expression Jews had so far been exempted; they could offer prayer ''for'' the emperor, rather than ''to'' him; far from a perfect compromise but the highest honour that Jewish tradition permitted in honour of a mortal. Caligula found this most unsatisfactory, and demanded that his statue be installed in the Temple of Jerusalem forthwith.{{sfn|Barrett|2015|pp=215–217}}

The [[Roman Governor|Governor]] of Syria, [[Publius Petronius]], ordered a statue from [[Sidon]], then postponed its installation for as long he could, rather than risk a serious Jewish rebellion.{{sfn|Philo|loc=''On the Embassy'' [[s:On the Embassy to Gaius#XXXI|XXXI.213]]}} In some versions, Caligula proved amenable to rational discussion with Agrippa and Jewish authorities, and faced with threats of rebellion, destruction of property and loss of the grain-harvest if the plan went ahead, abandoned the project. In more hostile versions Caligula, being demonstrably insane, and incapable of rational discussion, impulsively changed his mind once again, and reissued the order to Petronius along with the threat of enforced suicide if he failed. An even larger statue of Caligula-Zeus was ordered from Rome; the ship carrying it was still under way when news of Caligula's death reached Petronius. Caligula's plan was abandoned, Petronius survived and the statue was never installed.{{sfn|Josephus|loc=XVIII.8}}{{sfn|Barrett|2015|pp=214–216}}

Philo reports a rumour that in 40, Caligula announced to the Senate that he planned to move to Alexandria, and rule the Empire from there as a divine monarch, a [[Roman pharaoh]]. Very similar rumours attended Julius Caesar's last days, up to his assassination and very much to his discredit. Caligula's ancestor [[Mark Antony]] took refuge in Egypt with Cleopatra, and Augustus had made it a so-called "[[Imperial province]]", under his direct control. It was the main source of Italy's [[Cura Annonae|grain supply]], and was administered by members of the equestrian order, directly responsible to the ruling emperor. Egypt was, more or less, Caligula's property, to dispose of as he wished. Roman knowledge of pharaonic brother-sister marriages to maintain the royal bloodline would have shored up the many flimsy, scandalised allegations of adolescent incest between Caligula and Drusilla, supposedly discovered by Antonia but reported as rumour, and only by Suetonius. Barrett finds no further evidence for these allegations, and advises a skeptical attitude.{{sfn|Winterling|2011|pp=166–170}}{{sfn|Tacitus|loc=[[wikisource:The Annals (Tacitus)/Book 2#59|II.59]]}}{{sfn|Barrett|2015|pp=290–293}}

==== Germany and the Rhine frontier ====

In late 39 or early 40, Caligula ordered the concentration of military forces and supplies in upper Germany, and made his way there with a baggage train that supposedly included actors, gladiators, women, and a detachment of Praetorians. He might have meant to follow the paths of his father and grandfather, and attack the Germanic tribes along the upper Rhine; but according to ancient historians he was ill-prepared, and retreated in a panic. Modern historians, however, suppose that he had a valid political reason for his Germanic operation, and might even have been successful with that.{{sfn|Becker|1992|p=224}}{{sfn|Riemer|2006|p=73}} But the exact locations and enemies of his campaign cannot be determined; possibilities include the [[Chatti]] in and around modern-day [[Hesse]]{{sfn|Becker|1992|p=229}} or the [[Suebi]] east of the [[Upper Rhine]].{{sfn|Zimmermann|2018}}

The ancient sources report that Caligula used the opportunity of his operations in Germany to seize the wealth of rich allies whom he conveniently suspected of treason, "putting some to death on the grounds that they were 'plotting' or 'rebelling'".{{sfn|Barrett|2015|pp=19, 141–142}} Caligula accused the Imperial legate, [[Gnaeus Cornelius Lentulus Gaetulicus (consul 26)|Gaetulicus]], of "nefarious plots", and had him executed – according to Dio, he was killed for being popular with his troops.{{sfn|Barrett|2015|pp=171–176}} Lepidus, along with Caligula's two sisters, Agrippina and Livilla, was accused of being part of this conspiracy; he too was executed and Caligula's two sisters were exiled after being condemned ''pro forma'' for adultery.{{sfn|Wiedemann|1996|pp=226–227}}{{sfn|Cassius Dio|loc=LIX.22}}

A senatorial embassy arrived from Rome, headed by Caligula's uncle Claudius, to congratulate the emperor for suppressing this latest conspiracy. It met with a hostile reception, in which Claudius was supposedly ducked in the Rhine (though this might have been the loser's award in a contest of Latin and Greek oratory held by Caligula in Gaul that winter).{{sfn|Barrett|2015|p=68}} On Caligula's return from the north, he abandoned the theatre seating plans that Augustus had introduced so that rank alone would determine one's place. In the consequent free-for-all, seating was left to chance; doubtless to Caligula's pleasure, fights broke out as senators competed with common citizens for the best seats.{{sfn|Winterling|2011|pp=142–143}} Very late in his reign, possibly in its last few days, Caligula sent a communique in preparation for his imminent [[ovation]] in Rome, following his military activities in the North and his suppression of Lepidus. He announced that he would only be returning "to those who wanted him back"; to the "Equestrians and the People"; he did not mention the Senate or senators, of whom he had grown increasingly mistrustful.{{sfn|Barrett|2015|pp=142–144, 247–248}}

====Auctions====
In late 39, Caligula wintered at [[Lugdunum]] (modern [[Lyon]]) in Gaul, where he auctioned off his sisters' portable property, including their jewellery, slaves and freedmen. Dio claims that wealthy bidders at these auctions were willing to offer far more than items were worth; some to show their loyalty, and others to rid themselves of some of the wealth that could render their execution worthwhile.{{sfn|Cassius Dio|loc=LIX.14}} Caligula is said to have used intimidation and various auctioneer's tricks and tactics to boost prices.{{sfn|Barrett|2015|pp=299, 319 note 76}} In an event that Suetonius describes as "well known", a Praetorian gentleman, nodding off to sleep after a gladiator match, woke to find that he had bought 13 gladiators for the vastly over-inflated sum of 9 million [[sesterces]].{{sfn|Barrett|2015|pp=282, 298–300, citing Suet. ''Calig.'' 38.4}} Caligula's first Lugdunum auction proved such a successful fundraiser that he had many of the furnishings of his palace in Rome carted to Lugdunum and auctioned off; they included many precious family heirlooms. Caligula recited their provenance during the auction, in an attempt to help ensure a fair return on objects intrinsically valuable, and seemingly much sought after by the wealthy for their Imperial associations.{{sfn|Barrett|2015|pp=299, 319 note 76}}

Income from this second auction was relatively moderate. Kleijwegt (1996) describes Caligula's performance as vendor and auctioneer at this second auction as "completely out of character with the image of a tyrant". Auctions of Imperial property were acceptable ways to "balance the books", practiced by Augustus and later, by [[Trajan]]; they were expected to benefit the bidders as well as the vendor; Roman auctioneers were held in very low esteem, but Kleijwegt claims that Caligula seems to have behaved more like a benevolent ''princeps'' in this second auction, without malice, greed or intimidation.{{sfn|Suet. ''Calig.''|loc=38}}{{sfn|Cassius Dio|loc=LIX.14}}{{sfn|Barrett|2015|pp=299, 319 n. 76}}<ref>{{Cite journal |last=Kleijwegt |first=M |date=1996 |title=Caligula as Auctioneer |jstor=24594577 |journal=Acta Classica |volume=39 |pages=55–66 |issn=0065-1141}}</ref>

==== Britannia ====
In the spring of 40, Caligula tried to extend Roman rule into [[Roman Britain|Britannia]].{{sfn|Suet. ''Calig.''|loc=7}} Two legions had been raised for this purpose, both likely named ''Primigeniae'' in honour of Caligula's newborn daughter. Ancient sources depict Caligula as being too cowardly to have attacked or as mad, but stories of his threatening a [[Decimation (punishment)|decimation]] of his troops indicate mutinies. Broadly, "it is impossible to judge why the army never embarked" on the invasion. Beyond mutinies, it may have simply been that British chieftains acceded to Rome's demands, removing any justification for war.{{sfn|Cassius Dio|loc=LIX.25}}{{sfn|Wiedemann|1996|p=228}} Alternatively, it could have been merely a training and scouting mission<ref>{{Cite journal |last=Bicknell |first=Peter |date=1968 |title=The emperor Gaius' military activities in AD 40 |journal=Historia: Zeitschrift für Alte Geschichte |volume=17 |issue=4 |pages=496–505 |jstor=4435047 |issn=0018-2311}}</ref> or a short expedition to accept the surrender of the British chieftain [[Adminius]].<ref>{{Cite journal |last=Davies |first=R |date=1966 |title=The 'abortive invasion' of Britain by Gaius |journal=Historia: Zeitschrift für Alte Geschichte |volume=15 |issue=1 |pages=124–128 |jstor=4434915 |issn=0018-2311}}</ref><ref>{{Cite journal |last=Malloch |first=SJV |date=2001 |title=Gaius on the Channel coast |url=https://www.cambridge.org/core/journals/classical-quarterly/article/abs/gaius-on-the-channel-coast/242E051E4D729E6DD0FEC53A3915516A |journal=Classical Quarterly |volume=51 |issue=2 |pages=551–556 |doi=10.1093/cq/51.2.551 |issn=1471-6844|url-access=subscription }}</ref> Suetonius reports that Caligula ordered his men to collect seashells as "spoils of the sea"; this may also be a mistranslation of {{lang|la|musculi}}, meaning siege engines.{{sfn|Wiedemann|1996|p=228}}{{sfn|Suet. ''Calig.''|loc=45–47}} The conquest of Britannia was later achieved during the reign of Caligula's successor, Claudius.

==== Mauretania ====

[[File:Calig2en.png|thumb|left|300px|Map of the Roman Empire and neighboring states during the reign of Gaius Caligula (AD&nbsp;37–41) {{legend|#FE625B|Italy and Roman provinces}}{{legend|#65AAF4|Independent countries}}{{legend|#FEE05B|Client states (Roman puppets)}}{{legend|#FE85EA|Mauretania seized by Caligula}}{{legend|#976297|Former Roman provinces Thrace and Commagena made client states by Caligula}}]]

In 40, Caligula annexed [[Mauretania]],{{sfn|Suet. ''Calig.''|loc=7}} a wealthy, strategically significant [[client kingdom]] of Rome, inhabited by fiercely independent semi-nomads who resisted Romanisation. Its ruler, [[Ptolemy of Mauretania]], was a noble descendant of [[Juba II]], popular, extremely wealthy and with a reputation as "feckless and incompetent". Ptolemy failed to deal effectively with an uprising and was removed. The usual fate of incompetent client kings was retirement and a comfortable exile, but Caligula ordered Ptolemy to Rome and had him executed, some time after the spring of 40. His removal proved unpopular enough in Mauretania to provoke an uprising.{{sfn|Barrett|2015|pp=157–158}}

Rome divided Mauretania into two provinces, [[Mauretania Tingitana]] and [[Mauretania Caesariensis]], separated by the river [[Moulouya River|Malua]].{{sfn|Pliny the Elder|loc=[[s:Natural History (Rackham, Jones, & Eichholz)/Book 5|V.2]]}} Pliny claims that division was the work of Caligula, but Dio states that the uprising was subdued in 42 (after Caligula's death), by [[Gaius Suetonius Paulinus]] and [[Gnaeus Hosidius Geta]], and the division only took place after this.{{sfn|Cassius Dio|loc=[https://penelope.uchicago.edu/Thayer/E/Roman/Texts/Cassius_Dio/60*.html#8 LX.8]}} This confusion might mean that Caligula decided to divide the province, but postponed the division because of the rebellion. The first known equestrian governor of the joint provinces was [[Marcus Fadius Celer Flavianus]], in office in 44.{{sfn|Barrett|1989|p=118}}

Details on the Mauretanian events of 39–44 are lost, including an entire chapter by Dio on the annexation.{{sfn|Cassius Dio|loc=LIX.25}} Dio and Tacitus suggest that Caligula may have been motivated by fear, envy, and consideration of his own ignominious military performance in the north, rather than pressing military or economic needs.<ref>{{Cite journal |last=Sigman |first=Marlene C |date=1977 |title=The Romans and the indigenous tribes of Mauritania Tingitana |jstor=4435574 |journal=Historia: Zeitschrift für Alte Geschichte |volume=26 |issue=4 |pages=415–439 |issn=0018-2311}}</ref>{{page needed |date=August 2024}} The rebellion of [[Tacfarinas]] had shown how exposed Africa Proconsularis was to its west and how the Mauretanian client kings were unable to provide protection to the province, and it is thus possible that Caligula's expansion was a prudent and ultimately successful response to potential future threats.{{sfn|Barrett|2015|pp=158–161}}

=== Religion ===
[[File:Kunsthistorisches Museum Vienna June 2006 038.jpg|thumb|right|Cameo depicting Caligula and [[Roma (personification)|Roma]], a personification of [[Rome]]]]
According to Barrett, "[o]f all the manifestations of wild and extravagant behaviour exhibited by Caligula during his brief reign, nothing has better served to confirm the popular notion of his insanity than his apparent demand to be recognised as a god."{{sfn|Barrett|2015|p=190}}

Philo, Caligula's contemporary, claims that Caligula costumed himself as various heroes and deities, starting with demigods such as [[Dionysos]], [[Herakles]] and the [[Dioscuri]], and working up to major deities such as [[Mercury (mythology)|Mercury]], [[Venus (mythology)|Venus]] and [[Apollo]]. Philo describes these impersonations in a context of private pantomime or theatrical performances he may have witnessed or heard of during his diplomatic visit, as evidence that Caligula wanted to be venerated as a living god. Philo, as a Jew and a monotheist, took this as proof of the emperor's insanity.{{sfn|Philo|loc=''On the Embassy'' [[s:On the Embassy to Gaius#XI|XI–XV]]}}{{sfn|Pollini|2012|p=377}}

Caligula's impersonations had a precedent; Augustus had once thrown a party in which he and his guests dressed up as the Olympian gods; Augustus was made up and dressed as Apollo. No-one was thought insane in consequence, and none claimed to be the god they impersonated; but the event was not repeated. It showed near-blasphemous disrespect to the gods in question, and insensitivity to the population at large – the feast was staged during a famine. Coin issues of the official Roman mint, dated to the early 20s BC, show Octavian as Apollo, Jupiter and Neptune. This too may have been thought a transgression, and was not repeated.{{sfn|Beard|North|Price|1998|pp=209–210}} Caligula took his own impersonations less seriously than some, certainly less seriously than Philo did. According to Dio, when a Gallic shoemaker laughed to see Caligula dressed as Jupiter, pronouncing oracles at the crowd from a lofty place, Caligula asked "and who do you think I am?" The shoemaker answered "a complete idiot". Caligula seems to have appreciated his straightforward honesty.{{sfnm|Barrett|2015|1pp=196, 291–292|2a1=Barrett|2a2=Yardley|2y=2023|2pp=154–155}}<ref>{{harvnb|Suet. ''Aug.''|loc=70}}; {{harvnb|Suet. ''Calig.''|loc=52}}; {{harvnb|Cassius Dio|loc=59.26}}.</ref>

Dio claims that Caligula impersonated [[Jupiter (god)|Jupiter]] to seduce various women; that he sometimes referred to himself as a divinity in public meetings; and that he was sometimes referred to as "Jupiter" in public documents. Caligula's special interest in Jupiter as Rome's chief deity is confirmed by all surviving sources. Simpson{{relevance inline |reason=Is attribution here necessary? Who is C J Simpson? |date=August 2024 }} believes that Caligula may have considered Jupiter an equal, perhaps a rival.{{sfn|Simpson|1981|loc=passim<!-- More specific pages needed --> }}{{sfn|Cassius Dio|loc=LIX.26,28}}{{sfn|Pollini|2012|pp=387–79}}{{clarify |reason=Why is an attribution to Simpson's 1981 article cited to the article and then two other sources? Does Pollini support Simpson? Is Simpson citing Dio? If so, bundle. |date=August 2024 }}

According to Ittai Gradel,{{relevance inline |reason=Is attribution here necessary? Who is Gradel? |date=August 2024 }} Caligula's performances as various deities prove no more than a penchant for theatrical fancy-dress and a mischievous desire to shock; as emperor, Caligula was also ''[[pontifex maximus]]'', one of Rome's most powerful and influential state priests.{{sfn|Gradel|2002|pp=142–58}} The promotion of mortal rulers to godlike status, to honour their superior standing and perceived merits, was a commonplace phenomenon among Rome's eastern allies and client states; during their eastern tour, Germanicus, Agrippina and their children, including Caligula, were officially received as living deities by several cities of the Greek East.{{sfn|Winterling|2011|pp=20–21}} In Roman culture a [[Patronage in ancient Rome|client]] could flatter their living patron as "Jupiter on Earth", without reprimand.{{sfn|Gradel|2002|p=46, citing Plautus{{page needed |date=August 2024}} }} The [[Glossary of ancient Roman religion#divus|''divi'']] (deceased members of the Imperial family promoted to divine status) were creations of the Senate, who voted them into official existence, appointed their priesthood and granted them cult at state expense. Cicero could protest at the implications of Caesar's divine honours while living but address [[Publius Cornelius Lentulus Spinther|Publius Lentulus]] as ''parens ac deus'' (parent and god) to thank him for his help, as aedile, against the conspirator [[Catiline]]. Daily reverence was offered as a matter of course to patrons, heads of household and the powerful by their clients, families and social inferiors. In 30 BC, libation-offerings to the ''genius'' of Octavian (later Augustus) became a duty at public and private banquets, and from 12 BC, state oaths were sworn by the ''genius'' of Augustus as the living emperor.<ref>{{Cite book |last=Brent |first=Allen |title=The imperial cult and the development of church order: concepts and images of authority in paganism and Early Christianity before the Age of Cyprian |date=1999 |publisher=Brill |isbn=978-90-04-11420-3 |location=Leiden |page=61 }}</ref>{{sfn|Cassius Dio|loc=51.19.7}} Notwithstanding Dio's claims that cult to living emperors was forbidden in Rome itself, there is abundant evidence of municipal cult to Augustus in his lifetime, in Italy and elsewhere, locally organised and financed. As Gradel observes, no Roman was ever prosecuted for sacrificing to his emperor.{{sfn|Gradel|2002|pp=263–268}}

Caligula seems to have taken his religious duties very seriously. He found a replacement for the aged priest of [[Diana (mythology)|Diana]] at [[Lake Nemi]], reorganised the [[Salii]] (priests of [[Mars (mythology)|Mars]]), and pedantically insisted that as it was ''[[Glossary of ancient Roman religion#nefas|nefas]]'' (religiously improper) for Jupiter's leading priest, the [[Flamen Dialis]], to swear any oath, he could not swear the imperial oath of loyalty.{{sfn|Barrett|2015|p=195}}{{efn|Jupiter was the highest divine witness to oaths. The Flamen Dialis was sworn to his service, and was hedged about with an exhaustive range of prohibitions.{{citation needed |date=August 2024}} }} Caligula wished to take over or share the half-finished but splendid [[Temple of Apollo (Didyma)|Temple of Apollo]] in Greek Didyma for his own cult. Seemingly, his statue was prepared, but possibly not installed. When [[Pausanias (geographer)|Pausanias]] visited the still-unfinished temple a century later, its cult statue was of Apollo.{{sfn|Barrett|2015|pp=193f}}
[[File:Statue della famiglia giulio claudia, dal foro di veleia, 14-54 dc ca., caligola.jpg|thumb|240px|right|Contemporary statue portraying Caligula in his capacity as ''pontifex maximus'']]

Suetonius and Dio mention a temple to Caligula in the city of Rome. Most modern scholarship agrees that if such a temple existed, it was probably on the Palatine.{{sfn|Barrett|2015|pp=197–199}} Augustus had already linked the [[Temple of Castor and Pollux]] directly to his imperial residence on the Palatine, and established an official priesthood of lesser magistrates, the ''seviri Augustales'', usually drawn from his own freedmen to serve the ''genius Augusti'' (his "family spirit") and [[Lares]] (the twin ancestral spirits of his household).<ref>{{Cite book |last=Lott |first=John Bert |title=The neighborhoods of Augustan Rome |date=2004 |publisher=Cambridge University Press |isbn=978-0-521-82827-7 |pages=107–117, 172 }}</ref> Dio claims that Caligula stationed himself to receive veneration, dressed as Jupiter Latiaris, between the images of [[Castor and Pollux]], the twin Dioscuri, to whom he referred – humorously – as his doorkeepers.{{sfn|Cassius Dio|loc=LIX.28}}{{sfn|Barrett|2015|pp=196–197}}{{sfn|Beard|North|Price|1998|pp=209–210}} Dio's claim that two temples were built for Caligula in Rome,{{sfn|Cassius Dio|loc=LIX.28}} is unconfirmed. Simpson believes it likely that Caligula, voted a temple on the Palatine by the Senate, funded it himself.{{sfn|Simpson|1981|pp=506–507}}

An embassy from Greek states to Rome greeted Caligula as the "new god Augustus". In the Greek city of [[Cyzicus]], a public inscription from the beginning of Caligula's reign gives thanks to him as a "New Sun-god".{{sfn|Barrett|2015|p=192}} Egyptian provincial coinage and some state ''[[dupondii]]'' show Caligula enthroned; the first reigning Roman ''princeps'' to be described as the "New Sun", ({{transliteration|grc|Neos Helios}}) with the radiate crown of the Sun-god, or of Caligula's divine antecedent, the {{lang|la|[[divus]]}} Augustus. Caligula's image on other state coinage carries no such "trappings of divinity".{{sfn|Pollini|2012|pp=[https://books.google.com/books?id=KJDV1USNxQ0C&pg=PA151 150–151]}} Compared to the full-blown cults to major deities of state, ''genius'' cults were quite modest in scope. Augustus, once deceased, was officially worshipped as a {{lang|la|divus}} – immortal, but somewhat less than a full-blown deity; Tiberius, his successor, forbade his own personal cult outright in Rome itself, probably in consideration of Julius Caesar's assassination following his hubristic promotion as a living divinity.{{sfn|Cassius Dio|loc=51.20}} Augustus, and after him, Tiberius, insisted that if temples to honour them in the provinces were proposed by the local elite, they must be shared by the "genius of the Senate", or the personification of the Roman people, or the ''genius'' of Rome itself.{{sfn|Winterling|2011|pp=148–153}}

Dio claims that Caligula sold priesthoods for his unofficial ''genius'' cult to the wealthiest nobles, for a ''per capita'' fee of 10 million sesterces, and made loans available to those who could not afford immediate full payment. His priests supposedly included his wife, Caesonia, and his uncle [[Claudius]], whom Dio claims was bankrupted by the cost.{{sfn|Cassius Dio|loc=LIX.26–28}} The circumstances mark this out as private cult and personal humiliation among the wealthy elite, not subsidised by the Roman state. Throughout his reign, Caligula seems to have remained popular with the masses, in Rome and the empire. There is no sound evidence that he caused the removal, replacement or imposition of Roman or other deities, or even that he threatened to do so, outside the hostile anecdotes of his biographers. Barrett (2015) asserts that the "emphatic and unequivocal message of the material evidence is that Caligula had no desire for the world to identify him as a god, even if, like most people, he enjoyed being treated like one."{{sfn|Barrett| 2015|p=198}} He did not demand worship as a living god; but he permitted it when it was offered; Imperial etiquette, and the examples of Augustus and Tiberius, would have him refuse divine honours but thank those who offered them, inferring their status as equal to his.{{sfn|Winterling|2011|pp=150–154}} He seems to have taken his own ''genius'' cult very seriously but his fatal offense was to willfully "insult or offend everyone who mattered", including the military officers who assassinated him.{{sfnm|Gradel|2002|1pp=142–158|Simpson|1981|2p=503}}