Decades: 470s BC 460s BC 450s BC 440s BC 430s BC - **420s BC** - 410s BC 400s BC 390s BC 380s BC 370s BC

Years: 428 BC 427 BC 426 BC 425 BC 424 BC - **423 BC** - 422 BC 421 BC 420 BC 419 BC 418 BC

- Xerxes II, King of Persia is assassinated by orders of his half-brother and rival claimant Sogdianus.
- Sogdianus, King of Persia is assassinated by orders of his half-brother and rival claimant Darius II of Persia.
- Darius II becomes sole ruler of the Persian Empire.

**Deaths**

- Xerxes II, King of Persia (assassination).
- Sogdianus, King of Persia (assassination).