Council of Chalcedon
A dispute over Christ's nature splits the Christian East

In October 451 the council at Chalcedon declared that Christ is one person in two natures, divine and human. Many Christians in Egypt, Syria and Armenia rejected the decision, and the split with the Copts, Syrian Jacobites and Armenians has never been healed.
Wikipedia (Russian) · Wikipedia (English) · 5th century
Meanwhile around the world (±25 years)
Europe
- 455 Vandals sack Rome — 4 years later
- 476 Fall of the Western Roman Empire — 25 years later
Asia
- c. 427 Founding of Nalanda — 24 years earlier
Americas
- c. 431 Ilopango eruption — 20 years earlier
Alive at the time
- Attila (aged 45)