431 BC

Centuries:	6th century BC - 5th century BC - 4th century BC
Decades:	460s BC 450s BC 440s BC - 430s BC - 420s BC 410s BC 400s BC
Years:	434 BC 433 BC 432 BC - 431 BC - 430 BC 429 BC 428 BC

431 BC by topic
Politics
State leaders - Sovereign states
Birth and death categories
Births - Deaths
Establishments and disestablishments categories
Establishments - Disestablishments v • d • e

**431 BC in other calendars**
Gregorian calendar	431 BC
Ab urbe condita	323
Armenian calendar	N/A
Bahá'í calendar	-2274 – -2273
Berber calendar	520
Buddhist calendar	114
Burmese calendar	-1068
Chinese calendar	2206/2266 ([[Sexagenary cycle\|]]年) — to — 2207/2267 ([[Sexagenary cycle\|]]年)
Coptic calendar	-714 – -713
Ethiopian calendar	-438 – -437
Hebrew calendar	3330 – 3331
Hindu calendars
- Vikram Samvat	-375 – -374
- Shaka Samvat	N/A
- Kali Yuga	2671 – 2672
Holocene calendar	9570
Iranian calendar	1052 BP – 1051 BP
Islamic calendar	1084 BH – 1083 BH
Japanese calendar
Korean calendar	1903
Thai solar calendar	113
v • d • e

[edit] Events

Athens enters into an alliance with King Sitalkes of Thrace, after Nymphodorus, an influential Athenian, marries Sitalkes' sister. Nymphodorus then negotiates an agreement between Athens and Macedon's King Perdiccas II, through which Perdiccas regains Therma. As a result, Athens withdraws its support for Perdiccas' brother, Philip, and the Thracians promise to assist Perdiccas in capturing him. In return, Perdiccas marches on the Chalcidians, the people he has originally persuaded to revolt.
A Theban raid on Plataea, the only pro-Athenian city in Boeotia, is a failure and the Plataeans take 180 prisoners and put them to death. Athens supports Plataea while Sparta aligns itself with Thebes. Sparta enlists the help of the Greek cities in Italy and Sicily. Both Sparta and Athens appeal to Persia, but without result.
The Spartans, led by King Archidamus II, invade Attica effectively starting the Second Peloponnesian War between the Athenian Empire and the Peloponnesian League. The Spartans lay waste to the countryside around Athens. Athenian leader, Pericles, does not seriously oppose them, rather withdrawing the rural population of the country districts within Athens' city walls. Instead, he pursues active naval warfare and reduces any danger from the island of Aegina by replacing its native population with Athenians.

The Greek physician and philosopher Empedocles articulates the notion that the human body has four humours: blood, bile, black bile, and phlegm, a belief which dominates medical thinking for centuries.

Euripides' play Medea wins third prize at the Dionysia, the famous Athenian dramatic festival.