312 BC

Millennium:	1st millennium BC
Centuries:	5th century BC 4th century BC 3rd century BC
Decades:	330s BC 320s BC 310s BC 300s BC 290s BC
Years:	315 BC 314 BC 313 BC 312 BC 311 BC 310 BC 309 BC

312 BC in various calendars

Gregorian calendar	312 BC CCCXII BC
Ab urbe condita	442
Ancient Egypt era	XXXIII dynasty, 12
- Pharaoh	Ptolemy I Soter, 12
Ancient Greek era	117th Olympiad (victor)¹
Assyrian calendar	4439
Balinese saka calendar	N/A
Bengali calendar	−904
Berber calendar	639
Buddhist calendar	233
Burmese calendar	−949
Byzantine calendar	5197–5198
Chinese calendar	戊申年 (Earth Monkey) 2386 or 2179     — to — 己酉年 (Earth Rooster) 2387 or 2180
Coptic calendar	−595 – −594
Discordian calendar	855
Ethiopian calendar	−319 – −318
Hebrew calendar	3449–3450
Hindu calendars
- Vikram Samvat	−255 – −254
- Shaka Samvat	N/A
- Kali Yuga	2789–2790
Holocene calendar	9689
Iranian calendar	933 BP – 932 BP
Islamic calendar	962 BH – 961 BH
Javanese calendar	N/A
Julian calendar	N/A
Korean calendar	2022
Minguo calendar	2223 before ROC 民前2223年
Nanakshahi calendar	−1779
Seleucid era	0/1 AG
Thai solar calendar	231–232
Tibetan calendar	阳土猴年 (male Earth-Monkey) −185 or −566 or −1338     — to — 阴土鸡年 (female Earth-Rooster) −184 or −565 or −1337

Year 312 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Corvus and Mus (or, less frequently, year 442 Ab urbe condita). The denomination 312 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

Cyrenaica

• Ptolemy puts down a revolt in Cyrene.

Cyprus

• After putting down the revolt in Cyrene, Ptolemy travels to Cyprus with a great force. He arrests the rulers of Kition, Lapethus, Kyrenia, and Marion for being to friendly towards Antigonus and/or to hostile towards himself, he then establishes his friend Nicocreon of Salamis as Strategos of Cyprus.

Syria/Mesopotamia/Babylonia

• Ptolemy raids Antigonus' territories in Cilicia and Syria, and then sails back to Egypt.
• At the end of the year, Ptolemy invades Antigonus' territories in Palestine with an army of 18,000 infantry and 4,000 cavalry. The resulting Battle of Gaza leads to a triumph for Ptolemy over Antigonus' son, Demetrius Poliorcetes.
• Seleucus ceases his service to Ptolemy and returns to his former province, Babylonia. This event takes place on October 1 and becomes the starting point of the Seleucid era.

Greece/Macedon/Thrace

• Telesphorus enters Elis and fortifies the citadel, and enslaves the city.
• Cassander sails against the city of Oreus on Euboea with a fleet of 30 ships. He blockades its port trying to force the city's surrender.
• Telesphorus comes to the aid of Oreus from the Peloponnese with 1,000 soldiers and 20 ships, while Antigonid admiral Medius sails to relieve Oreus with a 100 ships from Asia Minor; they break Cassander's blockade.
• Cassander recieves reinforcements from Athens (under Thymochares the Sphettian, descendant of Thymochares) and defeats Telesphoros' squadron.
• Antigonus sends his nephew Ptolemy, whom he has made Strategos of Greece, with 5,000 infantry, 500 cavalry and 150 warships (he had recalled and reinforced Medius' fleet) to take command of all Antigonid forces in Greece.
• Cassander abandons the siege of Oreus, concentrating his forces at Chalcis to counter Ptolemy who has landed in Boeotia. Antigonus himself now marches his main army to the Hellespontine region threatening to invade Europe and attack Macedon, forcing Cassander to retreat to Macedon to prepare its defences.
• Antigonus arrives at the Propontis and tries to negotiate an alliance with Byzantium, but the city, at the urging of Lysimachus, remaines neutral; without it Antigonus gives up on the idea of crossing over into Europe.
• Ptolemy captures Chalcis, removes Cassander's garrison, but does not install a garrison of his own. Eretria and Carystus, both on Euboea as well, join Antigonus' alliance. Ptolemy crosses over to mainland Greece and captures Oropos, again removing Cassander's garrison, he then hands it over to, Antiochus' ally, the Boeotian League. After Oropos he invades Attica putting pressure on Athens to negotiate a truce. From Attica he marches on Thebes, captures it and removes Cassander's garrison. He moves on to Phocis drives out Cassander's garrisons in that region as well, and moves into Opuntian Locris, where he besieges Opus.
• Telesphorus , who had been subordinated to Antigonus' other nephew Ptolemy considered this an insult and ends his friendship with Antigonus through betrayal.
• Ptolemy soon restores the situation and persuades Telesphorus to give up his revolt.

Sicily

• The Syracusans ask for help against their tyrant Agathocles from the Carthaginians, who, fearing for their own possessions in Sicily, send a large force to the island.

Roman Republic

• The Roman censor, Appius Claudius Caecus, a patrician, enters office and begins construction of the Appian Way (the Via Appia) between Rome and Capua. He also embarks on a program of political reform, including the distribution of the landless citizens of Rome among the tribes, which at this time constitute basic political units. Appius also admits sons of freedmen into the Roman Senate. He also asserts the right of freed slaves to hold office.
• Rome gets its first pure drinking water as engineers complete the first aqueduct into the city, the Aqua Appia.

Deaths

• Peithon (son of Agenor)