Editing Caesar (title) (section)

==Later developments==
===Crisis of the Third Century===
The popularity of using the title ''caesar'' to designate heirs-apparent increased throughout the third century. Many of the soldier-emperors during the [[Crisis of the Third Century]] attempted to strengthen their legitimacy by naming their sons as heirs with the title of ''caesar'', namely [[Maximinus Thrax]], [[Philip the Arab]], [[Decius]], [[Trebonianus Gallus]], [[Gallienus]] and [[Carus]]. With the exception of [[Gaius Julius Verus Maximus|Verus Maximus]] and [[Valerian II]] all of them were later either promoted to the rank of ''[[Augustus (title)|augustus]]'' within their father's lifetime (like [[Philip II (Roman emperor)|Philip II]]) or succeeded as ''augusti'' after their father's death ([[Hostilian]] and [[Numerian]]). The same title would also be used in the [[Gallic Empire]], which operated autonomously from the rest of the Roman Empire from 260 to 274, with the final Gallic emperor [[Tetricus I]] appointing his heir [[Tetricus II]] as ''caesar'' and his consular colleague. 

Despite the best efforts of these emperors, however, the granting of this title does not seem to have made succession in this chaotic period any more stable. Almost all ''caesares'' would be killed before, or alongside, their fathers, or, at best, outlive them for a matter of months, as in the case of [[Hostilian]]. The sole ''caesar'' to successfully obtain the rank of ''augustus'' and rule for some time in his own right was [[Gordian III]], and even he was heavily controlled by his court.

===Tetrarchy and Diarchy===
In 293, [[Diocletian]] established the [[Tetrarchy]], a system of rule by two senior emperors and two junior colleagues. The two coequal senior emperors were styled identically to previous Emperors, as ''augustus'' (in plural, ''augusti''). The two junior colleagues were styled identically to previous Emperors-designate, as ''nobilissimus caesar''. Likewise, the junior colleagues retained the title ''caesar'' upon becoming full emperors. The ''caesares'' of this period are sometimes referred as "emperors", with the Tetrarchy being a "rule of four emperors", despite being clearly subordinate of the ''augusti'' and thus not actually sovereigns.<ref>{{Cite book |last=Potter |first=David S. |url=https://books.google.com/books?id=F5wAfRUNxRQC&pg=PA194 |title=A Companion to the Roman Empire |date=2008 |publisher=John Wiley & Sons |isbn=978-1-4051-7826-6 |pages=193–196}}</ref>

The Tetrarchy collapsed as soon as Diocletian stepped down in 305, resulting in a [[Civil wars of the Tetrarchy|lengthy civil war]]. Constantine reunited the Empire in 324, after defeating the Eastern emperor [[Licinius]]. The tetrarchic division of power was abandoned, although the divisions of the [[praetorian prefecture]]s were maintained. The title ''caesar'' continued to be used, but now merely as a ceremorial honorific for young heirs. Constantine had four ''caesares'' at the time of his death: his sons [[Constantius II]], [[Constantine II (emperor)|Constantine II]], [[Constans]] and his nephew [[Dalmatius]], with his eldest son [[Crispus]] having been executed in mysterious circumstances earlier in his reign. He would be succeeded only by his three sons, with Dalmatius dying in the summer of 337 in similarly murky circumstances.<ref name=":1">{{Cite book |last=McEvoy |first=Meaghan |url=https://books.google.com/books?id=lgygc7HDBt0C&pg=PA2 |title=Child Emperor Rule in the Late Roman West, AD 367-455 |date=2013 |publisher=OUP |isbn=978-0-19-966481-8 |pages=3–7}}</ref> Constantius II himself would nominate as ''caesares'' his cousins [[Constantius Gallus]] and [[Julian (emperor)|Julian]] in succession in the 350s, although he first executed Gallus and then found himself at war with Julian before his own death. After Julian's revolt of 360, the title fell out of imperial fashion for some time, with emperors preferring simply to elevate their sons directly to ''augustus'', starting with [[Gratian]] in 367.<ref name=":1" />

The title would be revived in 408 when [[Constantine III (Western Roman emperor)|Constantine III]] gave it to his son [[Constans II (son of Constantine III)|Constans II]],<ref>{{Cite book |last=Kent |first=John |url=https://books.google.com/books?id=uHPKDwAAQBAJ&pg=PA50 |title=Roman Imperial Coinage. Volume X |date=2018 |publisher=Spink Books |isbn=978-1-912667-37-6 |pages=50}}</ref> and then in 424 when [[Theodosius II]] gave it to his nephew [[Valentinian III]] before successfully installing him upon the western throne as ''augustus'' in 425.<ref name=":1" /> Thereafter it would receive limited use in the Eastern Empire; for example, it was given to [[Leo II (emperor)|Leo II]] in 472 several months before [[Leo I (emperor)|his grandfather]]'s death. In the Western Empire, [[Palladius (Caesar)|Palladius]], the son of emperor [[Petronius Maximus]], became the last person bearing the title ''caesar'' in 455.

=== Byzantine Empire ===
[[File:Byzantinischer Mosaizist um 1000 002.jpg|thumb|right|upright|The Roman emperor [[Constantine the Great]], mosaic in [[Hagia Sophia]], [[Constantinople]]]]
''Caesar'' or ''Kaisar'' ({{lang|grc|Καῖσαρ}}) remained a senior court title in the Eastern or [[Byzantine Empire]]. Originally, as in the classical [[Roman Empire]], it was used for the heir apparent, and was first among the "awarded" dignities. From the reign of [[Theodosius I]], however, most emperors chose to solidify the succession of their intended heirs by raising them to co-emperors, i.e. ''[[Augustus (title)|augustus]]''. Hence the title was more frequently awarded to second- and third-born sons, or to close and influential relatives of the Emperor:  for example, [[Alexios Mosele (Caesar)|Alexios Mosele]] who was the son-in-law of [[Theophilos (emperor)|Theophilos]] (ruled 829–842), [[Bardas]] who was the uncle and chief minister of [[Michael III]] (r. 842–867), and [[Nikephoros II]] (r. 963–969) who awarded the title to his father, [[Bardas Phokas the Elder|Bardas Phokas]].{{sfn|Bury|1911|p=36}}{{sfn|ODB|loc="Caesar" (A. Kazhdan), p. 363}} An exceptional case was the conferment of the dignity and its insignia to the [[First Bulgarian Empire|Bulgarian]] khan [[Tervel of Bulgaria|Tervel]] by [[Justinian II]] (r. 685–695, 705–711) who had helped him regain his throne in 705.{{sfn|ODB|loc="Caesar" (A. Kazhdan), p. 363}} The title was awarded to the brother of Empress [[Maria of Alania]], [[George II of Georgia]] in 1081.<ref>{{Cite book |last=Herrin |first=Judith |url=https://books.google.com/books?id=m3n_WmVo2U0C&pg=PA313 |title=Unrivalled Influence: Women and Empire in Byzantium |date=2013 |publisher=Princeton University Press |isbn=978-0-691-15321-6 |pages=313}}</ref>

The office enjoyed extensive privileges, great prestige and power. When [[Alexios I Komnenos]] created the title of ''[[sebastokrator]]'', ''kaisar'' became third in importance, and fourth after [[Manuel I Komnenos]] created the title of ''[[despot (court title)|despot]]'', which it remained until the end of the Empire. The feminine form was ''kaisarissa''. It remained an office of great importance, usually awarded to imperial relations, as well as a few high-ranking and distinguished officials, and only rarely awarded to foreigners.<ref>{{Cite book |last=Choniates |first=Nicetas |url=https://books.google.com/books?id=O8arrZPM8moC&pg=PA412 |title=O City of Byzantium: Annals of Niketas Choniatēs |date=1984 |publisher=Wayne State University Press |isbn=978-0-8143-1764-8 |pages=412}}</ref>

According to the ''[[Kletorologion|Klētorologion]]'' of 899, the Byzantine ''caesar''{{'}}s insignia were a crown without a cross, and the ceremony of a ''caesar''{{'}}s creation (in this case dating to [[Constantine V]]), is included in ''[[De Ceremoniis]]'' I.43.{{sfn|Bury|1911|pp=20, 36}} The title remained the highest in the imperial hierarchy until the introduction of the ''[[sebastokrator|sebastokratōr]]'' (a composite derived from ''[[sebastos]]'' and ''[[autokrator]]'', the Greek equivalents of ''[[Augustus (title)|augustus]]'' and ''[[imperator]]'') by [[Alexios I Komnenos]] (r. 1081–1118) and later of ''[[Despotes|despotēs]]'' by [[Manuel I Komnenos]] (r. 1143–1180). The title remained in existence through the last centuries of the Empire. In the [[Palaiologan period]], it was held by prominent nobles such as [[Alexios Strategopoulos]], but from the 14th century, it was mostly awarded to rulers of the [[Balkans]] such as the princes of [[Great Vlachia|Vlachia]], [[Medieval Serbian state|Serbia]] and [[Thessaly]].{{sfn|ODB|loc="Caesar" (A. Kazhdan), p. 363}}

[[File:Seal of the Caesar Michael Angelos (Schlumberger, 1900).png|thumb|Seal of the ''caesar'' Michael Angelos]]
In the late Byzantine hierarchy, as recorded in the mid-14th century ''Book of Offices'' of [[pseudo-Kodinos]], the rank continued to come after the ''sebastokratōr''. Pseudo-Kodinos further records that the ''caesar'' was equal in precedence to the ''[[panhypersebastos]]'', another creation of Alexios I, but that Emperor [[Michael VIII Palaiologos]] (r. 1259–1282) had raised his nephew [[Michael Tarchaneiotes]] to the rank of ''[[protovestiarios]]'' and decreed that to come after the ''caesar''; while under [[Andronikos II Palaiologos]] (r. 1282–1328) the ''[[megas domestikos]]'' was raised to the same eminence, when it was awarded to the future emperor [[John VI Kantakouzenos]] (r. 1347–1354).{{sfn|Verpeaux|1966|pp=134–136}} According to pseudo-Kodinos, the ''caesar''{{'}}s insignia under the Palaiologoi was a ''skiadion'' hat in red and gold, decorated with gold-wire embroideries, with a veil bearing the wearer's name and [[Pendilia|pendants]] identical to those of the ''despotēs'' and the ''sebastokratōr''. He wore a red tunic (''rouchon'') similar to the emperor's (without certain decorations), and his shoes and stockings were blue, as were the accouterments of his horse; these were all identical to those of the ''sebastokratōr'', but without the embroidered eagles of the latter. Pseudo-Kodinos writes that the particular forms of another form of hat, the domed ''skaranikon'', and of the mantle, the ''tamparion'', for the ''caesar'' were not known.{{sfn|Verpeaux|1966|pp=147–149}}

===Ottoman Empire===
{{Main|Ottoman claim to Roman succession}}
[[File:Gennadios II and Mehmed II.jpg|thumb|right|upright|[[Mehmed II]] and Ecumenical Patriarch of Constantinople [[Gennadius Scholarius|Gennadios]].]]
"Caesar" is the title officially used by the [[Sasanian Empire|Sasanid Persians]] to refer to the Roman and Byzantine emperors.<ref>{{langx|pal|[[wikt:𐭪𐭩𐭮𐭫𐭩|𐭪𐭩𐭮𐭫𐭩]]}} kysly ([[Inscriptional Pahlavi]]), kysl ([[Book Pahlavi]]), transcribed as ''kēsar''</ref><ref>{{cite book |last1=Hurbanič |first1=Martin |title=The Avar Siege of Constantinople in 626: History and Legend |date=2019 |publisher=Springer |isbn=978-3-030-16684-7 |page=234 |language=en}}</ref> In the [[Middle East]], the Persians and the Arabs continued to refer to the Roman and Byzantine emperors as "Caesar" (in {{langx|fa|قیصر روم}} ''Qaysar-i Rum'', "Caesar of the Romans", from [[Middle Persian]] ''kēsar''). Thus, following the [[Fall of Constantinople|conquest of Constantinople]] in 1453, the victorious [[Ottoman sultan]] [[Mehmed II]] became the first of the rulers of the [[Ottoman Empire]] to assume the title (in {{langx|ota|قیصر روم}} ''Kayser-i Rûm''). 

After the Fall of Constantinople, having conquered the Byzantine Empire, Mehmed took the title ''[[Kayser-i Rûm]]'', claiming succession to the Roman imperium.<ref>{{cite book|author1=Michalis N. Michael|author2=Matthias Kappler|author3=Eftihios Gavriel|title=Archivum Ottomanicum|url=https://books.google.com/books?id=SjwMAQAAMAAJ|year=2009|publisher=Mouton|page=10|isbn=978-3447057530}}</ref> His claim was that, by possession of the city, he was emperor, a new dynast [[Right of conquest|by conquest]], as had been done previously by the likes of [[Heraclius]] and [[Leo III the Isaurian|Leo III]].<ref>{{cite book|author1=Christine Isom-Verhaaren|author2=Kent F. Schull|title=Living in the Ottoman Realm: Empire and Identity, 13th to 20th Centuries|url=https://books.google.com/books?id=ZX2_CwAAQBAJ&pg=PA38|date=11 April 2016|publisher=Indiana University Press|isbn=978-0-253-01948-6|pages=38–}}</ref> Contemporary scholar [[George of Trebizond]] wrote "the seat of the Roman Empire is Constantinople ... and he who is and remains Emperor of the Romans is also the Emperor of the whole world".<ref name="Crowley2009">{{cite book|first=Roger |last=Crowley|title=Constantinople: The Last Great Siege, 1453|url=https://books.google.com/books?id=ftOp1cR7VK8C&pg=PT13|year=2009|publisher=Faber & Faber|isbn=978-0-571-25079-0|pages=13–}}</ref> 

[[Gennadius Scholarius|Gennadius II]], a staunch antagonist of the West because of the [[Sack of Constantinople]] committed by the Western Catholics and theological controversies between the two Churches, had been enthroned the [[Ecumenical Patriarch of Constantinople|Ecumenical Patriarch of Constantinople-New Rome]] with all the ceremonial elements and [[ethnarch]] (or ''milletbashi'') status by the Sultan himself in 1454. In turn, Gennadius II formally recognized Mehmed as successor to the throne.<ref>{{cite encyclopedia|url=https://global.britannica.com/biography/Gennadios-II-Scholarios|title= Gennadios II Scholarios |encyclopedia=Encyclopaedia Britannica |access-date=13 July 2020}}</ref> Mehmed also had a blood lineage to the Byzantine Imperial family; his predecessor, Sultan [[Orhan]] had married a Byzantine princess, and Mehmed may have claimed descent from [[John Tzelepes Komnenos]].<ref name="Norwich 1995 413–416">{{Cite book| last = Norwich | first = John Julius | author-link = John Julius Norwich  | year = 1995 | title = Byzantium:The Decline and Fall | pages = 81–82 | publisher = Alfred A. Knopf  | location = New York | isbn = 0-679-41650-1}}</ref> Ottoman sultans were not the only rulers to claim such a title, as there was the [[Holy Roman Empire]] in Western Europe, whose emperor, [[Frederick III, Holy Roman Emperor|Frederick III]], traced his titular lineage from [[Charlemagne]] who obtained the title of Roman Emperor when he was crowned by [[Pope Leo III]] in 800, although he was never recognized as such by the Byzantine Empire. 

In diplomatic writings between the Ottomans and Austrians, the Ottoman bureaucracy was angered by their use of the Caesar title when the Ottomans saw themself as the true successors of [[Roman Empire|Rome]]. When war broke out and peace negotiations were done, the Austrians ([[Holy Roman Empire]]) agreed to give up the use of the [[Julius Caesar|Caesar]] title according to [[Treaty of Constantinople (1533)]] (though they would continue to use it and the Roman imperial title until the collapse of the Holy Roman Empire in 1806). The Russians, who defined [[Moscow]] as the [[Third Rome]], were similarly sanctioned by the Ottomans, who ordered the [[Crimean Khanate]] to raid Russia on numerous occasions.<ref>{{Cite book|title=Kırım Hanlığı Tarihi Üzerine Araştırmalar 1441–1700: Seçme Eserleri – XI|last=Halil|first=Inançik|year=2017|publisher=Türkiye İş Bankası Kültür Yayınları |isbn=978-6052952511}}</ref> The Ottomans stopped claiming political superiority over the Holy Roman Empire with the [[Peace of Zsitvatorok|Treaty of Zsitvatorok]] in 1606, and over the [[Russian Empire]] with the [[Treaty of Küçük Kaynarca]] in 1774, by diplomatically recognising the monarchs of these two countries as equals to the Ottoman Sultan for the first time.