Editing Caesar (title) (section)

===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.