Editing Constantius II (section)

{{short description|Roman emperor from 337 to 361}}
{{distinguish|Constantine II (disambiguation){{!}}Constantine II|Julius Constantius|Constantius III}}
{{Use dmy dates|date=September 2021}}
{{Infobox royalty
| name         = Constantius II
| image        = Bust of Constantius II (Mary Harrsch).jpg
| image_size   =
| alt          = Head portrait of Constantius II
| caption      = Possible head portrait of Constantius II found in modern [[al-Bab]], [[Syria]] ([[Penn Museum]])<ref>{{Cite book |last1=Koçak |first1=Mustafa |url=https://books.google.com/books?id=j7WbEAAAQBAJ&pg=PA213 |title=Sculptures from Roman Syria II: The Greek, Roman and Byzantine Marble Statuary |last2=Kreikenbom |first2=Detlev |date=2022|publisher=Walter de Gruyter|isbn=978-3-11-071152-3|pages=213–215}}</ref><ref>[https://www.penn.museum/collections/object/106738 "Statue"]. ''[[Penn Museum]]''</ref>
| succession   = [[Roman emperor]]
| reign        = 9 September 337 – {{no wrap|3 November 361}}
| reign-type   = [[Augustus (title)|''Augustus'']]
| predecessor  = [[Constantine the Great|Constantine I]]
| successor    = [[Julian (emperor)|Julian]]
| regent       = {{Collapsible list|title=''See list''|{{ubl
 |[[Constantine II (emperor)|Constantine II]] (337–340){{efn|In the [[Praetorian prefecture of Gaul]].}}
 |[[Constans|Constans I]] (337–350){{efn|In the [[Praetorian prefecture of Italy]], then the whole [[Western Roman Empire]].}}
 |[[Magnentius]] (350–353){{efn|In the West, unrecognized by Constantius II.}}
 |[[Vetranio]] (350){{efn|In the West, against Magnentius.}}
 |[[Nepotianus]] (350){{efn|In Rome for 27 days, against Magnentius.}}
 |Julian (360–361){{efn|In rebellion against Constantius II.}}}} }}
| reg-type     = {{nowrap|Co-rulers}}
| reign1       = 8 November 324 – {{nowrap|9 September 337}}
| reign-type1  = [[Caesar (title)|''Caesar'']]
| birth_date   = 7 August 317
| birth_place  = [[Sirmium]], [[Pannonia Inferior]]
| death_date   = 3 November 361 (aged 44)
| death_place  = [[Mopsuestia]], [[Cilicia]]
| burial_place = [[Church of the Holy Apostles]]
| spouse       = [[Daughter of Julius Constantius]]<br/>[[Eusebia (empress)|Eusebia]]<br/>[[Faustina (wife of Constantius II)|Faustina]]
| issue        = [[Constantia (wife of Gratian)]]
| full name    = Flavius Julius Constantius<ref>CIL 06, 40776 = AE 1934, 00158 = AE 1950, 00174 = AE 1951, 00102 = AE 1982, 00011</ref>
| regnal name  = Imperator Caesar Flavius Julius Constantius Augustus
| dynasty      = [[Constantinian dynasty|Constantinian]]
| father       = [[Constantine the Great]]
| mother       = [[Fausta]]
| religion     = [[Semi-Arianism]]
}}

'''Constantius II''' ({{langx|la|Flavius Julius Constantius}}; {{langx|grc|Κωνστάντιος|Kōnstántios}}; 7 August 317 – 3 November 361) was [[Roman emperor]] from 337 to 361. His reign saw constant warfare on the borders against the [[Sasanian Empire]] and [[Germanic peoples]], while internally the [[Roman Empire]] went through repeated civil wars, court intrigues, and [[List of Roman usurpers|usurpations]]. His religious policies inflamed domestic conflicts that would continue after his death.

Constantius was a son of [[Constantine the Great]], who elevated him to the imperial rank of ''[[Caesar (title)|Caesar]]'' on 8 November 324 and after whose death Constantius became ''[[Augustus (title)|Augustus]]'' together with his brothers, [[Constantine II (emperor)|Constantine II]] and [[Constans]] on 9 September 337. He promptly oversaw the massacre of his [[Julius Constantius|father-in-law]], an [[Flavius Dalmatius|uncle]], and several cousins, consolidating his hold on power. The brothers divided the empire among themselves, with Constantius receiving [[Greece in the Roman era|Greece]], [[Thrace]], the Asian provinces, and [[History of Roman Egypt|Egypt]] in the east. For the following decade a costly and inconclusive [[Persian wars of Constantius II|war]] against [[Sasanian Persia|Persia]] took most of Constantius's time and attention. In the meantime, his brothers Constantine and Constans warred over the western provinces of the empire, leaving the former dead in 340 and the latter as sole ruler of the west. The two remaining brothers maintained an uneasy peace with each other until, in 350, Constans was overthrown and assassinated by the usurper [[Magnentius]].

Unwilling to accept Magnentius as co-ruler, Constantius waged a [[Roman civil war of 350–353|civil war]] against the usurper, defeating him at the battles of [[Battle of Mursa Major|Mursa Major]] in 351 and [[Battle of Mons Seleucus|Mons Seleucus]] in 353. Magnentius died by suicide after the latter battle, leaving Constantius as sole ruler of the empire. In 351, Constantius elevated his cousin [[Constantius Gallus]] to the subordinate rank of ''Caesar'' to rule in the east, but had him executed three years later after receiving scathing reports of his violent and corrupt nature. Shortly thereafter, in 355, Constantius promoted his last surviving cousin, Gallus's younger half-brother [[Julian (emperor)|Julian]], to the rank of ''Caesar''.

As emperor, Constantius promoted [[Arianism]], banned pagan sacrifices, and issued laws against [[Jews]]. His military campaigns against Germanic tribes were successful: he defeated the [[Alamanni]] in 354 and campaigned across the [[Danube]] against the [[Quadi]] and [[Sarmatians]] in 357. The war against the Sasanians, which had been in a lull since 350, erupted with renewed intensity in 359 and Constantius travelled to the east in 360 to restore stability after the loss of several border fortresses. However, Julian claimed the rank of ''Augustus'' in 360, leading to war between the two after Constantius's attempts to persuade Julian to back down failed. No battle was fought, as Constantius became ill and died of fever on 3 November 361 in [[Mopsuestia]], allegedly naming Julian as his rightful successor before his death.