Flavius Arbitio (

fl. ''Floruit'' ( ; usually abbreviated fl. or occasionally flor.; from Latin for 'flourished') denotes a date or period during which a person was known to have been alive or active. In English, the unabbreviated word may also be used as a noun indic ...

354–366 AD) was a Roman general and Consul who lived in the middle of the 4th century AD.

In the reign of Constantius II

Arbitio was a general of

Constantine I Constantine I (27 February 27222 May 337), also known as Constantine the Great, was a Roman emperor from AD 306 to 337 and the first Roman emperor to convert to Christianity. He played a Constantine the Great and Christianity, pivotal ro ...

. Under

Constantius II Constantius II (; ; 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 civ ...

, the son and successor of Constantine, he became magister equitum (commander of the cavalry). Arbitio was a well trusted courtier of Constantius, and some modern historians have suggested he was his military strongman. In 355 he was made

consul Consul (abbrev. ''cos.''; Latin plural ''consules'') was the title of one of the two chief magistrates of the Roman Republic, and subsequently also an important title under the Roman Empire. The title was used in other European city-states thro ...

together with Quintus Flavius Maesius Egnatius Lollianus. Arbitio intrigued against Claudius Silvanus, Ursicinus and Barbatio and played a role in their downfalls. Historian

Ammianus Marcellinus Ammianus Marcellinus, occasionally anglicized as Ammian ( Greek: Αμμιανός Μαρκελλίνος; born , died 400), was a Greek and Roman soldier and historian who wrote the penultimate major historical account surviving from antiquit ...

says he was "keen and eager in plotting treachery", and describes him as "fickle flatterer" to Constantius II.

In the reign of Julian

After the death of Constantius in 361, Arbitio was appointed chairman of the Chalcedon tribunal by the new Emperor Julian. In this function he was responsible for the conviction of Paulus Catena and many ministers and followers of Constantius. Arbitio did not take part in

Julian's Persian expedition Julian's Persian expedition began in March 363 AD and was the final military campaign of the Roman emperor Julian (emperor), Julian. The Romans fought against the Sasanian Empire, ruled at the time by Shapur II. Aiming to capture the Sasanians ...

, instead retiring to live as a private citizen.

In the reign of Valens

In 365,

Procopius Procopius of Caesarea (; ''Prokópios ho Kaisareús''; ; – 565) was a prominent Late antiquity, late antique Byzantine Greeks, Greek scholar and historian from Caesarea Maritima. Accompanying the Roman general Belisarius in Justinian I, Empe ...

, a relative of the deceased emperor Julian, attempted to seize control of the Roman Empire's eastern half from

Valens Valens (; ; 328 – 9 August 378) was Roman emperor from 364 to 378. Following a largely unremarkable military career, he was named co-emperor by his elder brother Valentinian I, who gave him the Byzantine Empire, eastern half of the Roman Em ...

. Arbitio ignored a summons from Procopius, and the usurper, who had been hoping to arrange an alliance, instead confiscated Arbitio's properties. This action led Arbitio to side with Valens, who appointed him "ad hoc ''magister militum''". During the subsequent campaign, Arbitio encountered an old friend, Gomoarius, serving in the opposing army, and convinced him to desert to Valens. Procopius was eventually captured and executed.Ammianus Marcellinus, 26.9.9 What happened to Arbitio after this time is unknown, although it is reasonable to assume that he retired, and subsequently died without taking any further part in matters of state.

Footnotes

Sources

, Loeb Classical Library * Lenski, N.E., ''Failure of empire: Valens and the Roman State in the fourth century A.D. (2002) {{end 4th-century Gallo-Roman people Ancient Roman generals Generals of Constantine the Great Generals of Constantius II Generals of Valens 4th-century Roman consuls Magistri equitum (Roman Empire)