__NOTOC__
Year 431 BC was a year of the pre-Julian Roman calendar. At the time, to Romans it was known as the Year of the Consulship of Cincinnatus and Mento (or, less frequently, year 323 Ab urbe condita). The denomination 431 BC for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
Events
<onlyinclude>
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.
Literature
- Euripides' play Medea wins third prize at the Dionysia, the famous Athenian dramatic festival.
</onlyinclude>
Births
- Xenophon, Athenian Greek mercenary and writer (d. c. 354 BC)
Deaths
- Phidias returns to Athens, where he is imprisoned (for having been portrayed on the shield of the statue of the goddess Athena) and dies before the trial.