500s | dp2=510s | dp1=520s | d=530s | dn1=540s | dn2=550s | dn3=560s }} Events By Place Byzantine Empire April 19 — Belisarius's defeated at the Battle of Callinicum; Mundus briefly takes command of the army. Some members of the Blue and Green chariot racing factions in Constantinople are imprisoned for murder, precipitating the Nika riots the next year. The building of St. Sophia Basilica, Constantinople,'s begun, and's completed in 537. Europe Theudis succeeds Amalaric as king of… (More on 531)