Decades: 480s BC 470s BC 460s BC 450s BC 440s BC - **430s BC** - 420s BC 410s BC 400s BC 390s BC 380s BC

Years: 436 BC 435 BC 434 BC 433 BC 432 BC - **431 BC** - 430 BC 429 BC 428 BC 427 BC 426 BC

**Events**

- Beginning of the Peloponnesian War
- The Greek physician and philosopher Empedocles articulates the notion that the human body has four humors- blood, bile, black bile, and phlegm, a belief which dominates medical thinking for centuries.

**Deaths**