Decades: 400s 410s 420s 430s 440s - 450s - 460s 470s 480s 490s 500s

Years: 446 447 448 449 450 - 451 - 452 453 454 455 456

• September 20 - Attila, king of the Huns, invades Gaul, but is stopped in his tracks at Troyes by Aetius in the Battle of Chalons.
• Thorismund succeeds Theodorid his father as king of the Visigoths.
• October 8 - Council of Chalcedon, Ecumenical council of the Christian church.
• Jerusalem becomes a Patriarchate.
• The Oriental Orthodox churches separate from the rest of the church.
• Dioscorus of Alexandria is deposed as Patriarch of Antioch.
• Sassanid ruler Yazdegerd II of Persia's decree abolishes the Sabbath and orders executions of Jewish leaders, including the Exilarch Mar Nuna.

• Jacob of Serugh - Syriac author

• Nestorius, founder of Nestorianism (estimated date)
• Theodorid, king of the Visigoths (killed in the Battle of Chalons)