431 BC

Millennium:	1st millennium BC
Centuries:	6th century BC 5th century BC 4th century BC
Decades:	450s BC 440s BC 430s BC 420s BC 410s BC
Years:	434 BC 433 BC 432 BC 431 BC 430 BC 429 BC 428 BC

431 BC in various calendars

Gregorian calendar	431 BC CDXXXI BC
Ab urbe condita	323
Ancient Egypt era	XXVII dynasty, 95
- Pharaoh	Artaxerxes I of Persia, 35
Ancient Greek era	87th Olympiad, year 2
Assyrian calendar	4320
Balinese saka calendar	N/A
Bengali calendar	−1023
Berber calendar	520
Buddhist calendar	114
Burmese calendar	−1068
Byzantine calendar	5078–5079
Chinese calendar	己酉年 (Earth Rooster) 2267 or 2060     — to — 庚戌年 (Metal Dog) 2268 or 2061
Coptic calendar	−714 – −713
Discordian calendar	736
Ethiopian calendar	−438 – −437
Hebrew calendar	3330–3331
Hindu calendars
- Vikram Samvat	−374 – −373
- Shaka Samvat	N/A
- Kali Yuga	2670–2671
Holocene calendar	9570
Iranian calendar	1052 BP – 1051 BP
Islamic calendar	1084 BH – 1083 BH
Javanese calendar	N/A
Julian calendar	N/A
Korean calendar	1903
Minguo calendar	2342 before ROC 民前2342年
Nanakshahi calendar	−1898
Thai solar calendar	112–113
Tibetan calendar	阴土鸡年 (female Earth-Rooster) −304 or −685 or −1457     — to — 阳金狗年 (male Iron-Dog) −303 or −684 or −1456

Year 431 BC was a year of the pre-Julian Roman calendar. At the time, 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

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 on the Mount Algidus.

By topic

Anatomy

• The Greek philosopher Empedocles distinguishes the four elements - earth, fire, water, and air - that he claims all substances are made of. He explains the development of the universe by the forces of attraction and repulsion known as Love and Strife.

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)