Decades: 450s BC 440s BC 430s BC 420s BC 410s BC - **400s BC** - 390s BC 380s BC 370s BC 360s BC 350s BC

Years: 406 BC 405 BC 404 BC 403 BC 402 BC - **401 BC** - 400 BC 399 BC 398 BC 397 BC 396 BC

- Agesilaus II becomes king of Sparta
- Battle of Cunaxa: Cyrus the Younger revolts against Artaxerxes II of Persia with help of ten thousand Greek mercenaries, but is defeated. Xenophon leads the surviving Greeks in a retreat home.
- Zhou an wang becomes King of the Zhou Dynasty of China.

**Deaths**

- Thucydides, Greek historian (approximate year)