257

By place

Roman Empire

• Gallienus enters into a joint consulship with his father Valerianus I, having brought some order to the Danube area.
• Future emperor Aurelian defeats the Goths and brings many prisoners back to Rome.
• In Bavaria the Limes Germanicus along the river Iller is abandoned by the Romans.
• Valerian, under guardianship of Ingenuus, is established at Sirmium to represent the Roman government in the troubled Illyrian provinces.
• Emperor Valerian recovers Antioch in Syria from the Persian king Shapur I.
• The Goths build a fleet on the Black Sea.
• The Goths separate into the Ostrogoths and the Visigoths.

  By topic

Religion

• August 30 - Pope Sixtus II succeeds Pope Stephen I as the 24th pope.
• Valerian's persecution of Christians begins: his edict orders bishops and priests to sacrifice according to the pagan rituals, and prohibits Christians, under penalty of death, from meeting at the tombs of their deceased.