Centuries: 8th century - 9th century - 10th century
- Patriarch Ignatius is imprisoned and (December 25) deposed to be succeeded by patriarch Photius I.
- Louis the German invades West Francia, hoping to secure Aquitaine from his brother Charles the Bald, but fails.
- Emperor Seiwa ascends the throne of Japan.
- Nicholas I becomes pope.
- Donald I succeeds the throne of Scotland.