355

At the time, it was known as the Year of the Consulship of Arbitio and Maesius (or, less frequently, year 1108 Ab urbe condita). The denomination 355 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

By place

Roman Empire

• January 1 – Arbitio and Lollianus Mavortius begin their term as Roman consuls.
• August 11 – Claudius Silvanus, accused of treason, proclaims himself Roman Emperor. After 28 days, Ursicinus arrives from Rome and has Silvanus murdered.
• November 6 – In Mediolanum (Italy), Emperor Constantius II raises his cousin Julian the Apostate to the rank of Caesar. He takes command of the western provinces and marries Constantius' sister, Helena.

Europe

• The Lentienses, a Germanic tribe, are fined by the Roman commander Arbetio under Constantius II for several incursions against the Roman Empire.
• The Franks besiege Colonia Agrippinensium for ten months.

Asia

• The Huns of Central Asia begin their great drive westwards with an advance into Scythia (modern Russia). They overcome and absorb the Alans, a nomadic and warlike horse breeding people from the steppes northeast of the Black Sea.

By topic

Religion

• Pope Liberius refuses to sign a condemnation of Athanasius, Patriarch of Alexandria, imposed at Milan by Constantius II. Liberius is exiled to Beroea (Greece) and replaced by Felix II. He becomes an antipope and bishop of Rome.

• Fan Tai, Chinese general of the Jin Dynasty (d. 428)
• Murong Bao, Chinese emperor of Later Yan (d. 398)

• September 7 – Claudius Silvanus, Roman usurper
• Aedesius, Roman Neoplatonist philosopher and mystic
• Fu Jian, Chinese emperor of the Former Qin (b. 317)
• Liang, Chinese empress of the Former Qin Dynasty
• Zhang Yaoling, Chinese ruler of Former Liang (b. 344)
• Zhang Zuo (or Taibo), Chinese ruler of Former Liang