306 BC

By place

Cyprus

• Demetrius Poliorcetes lands on Cyprus and besieges Menelaus, brother of Egypt's ruler, Ptolemy I Soter, at Salamis. Ptolemy I Soter, coming to his brother's aid, is decisively defeated in the Battle of Salamis. The battle completely destroys the naval power of Egypt and results in the capture of Cyprus by Demetrius Poliorcetes This gives Demetrius Poliorcetes' father, Antigonus I Monophthalmus, control of the Aegean and the eastern Mediterranean.
• Antigonus I Monophthalmus uses the occasion to assume the title of king, vacant since the murder of Alexander IV of Macedon. He immediately declares Demetrius Poliorcetes his co-ruler.

  Syria

• Antigonus I Monophthalmus proclaims himself king of Asia Minor and northern Syria thus commencing the Antigonid dynasty. Antigonus I Monophthalmus appoints Demetrius Poliorcetes king and co-regent.

  Sicily

• A peace agreement is reached between Syracuse and Carthage. The peace restricts Carthaginian power in Sicily to the area west of the Halycus River. This agreement allows the tyrant of Syracuse, Agathocles, to strengthen his rule over the Greek cities of Sicily.

  Egypt

• Antigonus I Monophthalmus tries to follow up his victory in Cyprus by invading Egypt with a large army and a formidable fleet. But Ptolemy I Soter successfully holds the frontier against him. However, the year's events mean that Ptolemy I Soter no longer engages in overseas expeditions against Antigonus I Monophthalmus.

  Thrace

• A four-drachma coin, picturing Alexander the Great, is issued by Lysimachos from this time until 281 BC. At least one of them is now preserved at the British Museum in London.