Events

By place

Western Roman Empire

• April 7—The Huns sack Metz.
• June 20—Battle of Chalons: The Huns and the Ostrogoths, facing the Romans and the Visigoths, achieve at best a draw. After the battle, between 10,000 and 20,000 men lie dead on the Catalaunian Fields.

Europe

• Battle of Vartanantz: The Armenian army is defeated by the Persians, and their rebel leader, Saint Vartan, dies. Despite the loss, Armenians consider this battle to have been a moral and religious victory, since the Persian king, out of respect for their efforts, allows them to remain Christian. The anniversary is a national and religious holiday.

Asia

• Sassanid ruler Yazdegerd II's decree abolishes the Sabbath, and orders executions of Jewish leaders, including the Exilarch Mar Nuna.

By topic

Religion

• October 8—Council of Chalcedon, Ecumenical council of the Christian church. As a result of this council the Oriental Orthodox churches became a separate communion.
• Jerusalem becomes a Patriarchate.
• Dioscorus of Alexandria is deposed as Patriarch of Antioch.

Births

• Jacob of Serugh, Syriac author
• Brigid of Ireland, Irish saint

Deaths

• Theodoric I, king of the Visigoths (killed in battle)
• Liu Yikang
• Tuoba Huang