431 BC

Events

By place

Greece

• 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.

Roman Republic

• The Romans defeat the Aequi and the Volsci at the battle of the River Algidus.

By topic

Anatomy

• 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.

Literature

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

Births

• Xenophon, Greek mercenary and writer (d. c. 355 BC)

Deaths