285 BC

Millennium:	1st millennium BC
Centuries:	4th century BC – 3rd century BC – 2nd century BC
Decades:	310s BC 300s BC 290s BC – 280s BC – 270s BC 260s BC 250s BC
Years:	288 BC 287 BC 286 BC – 285 BC – 284 BC 283 BC 282 BC

285 BC by topic
Politics
State leaders – Sovereign states
Birth and death categories
Births – Deaths
Establishments and disestablishments categories
Establishments – Disestablishments

Events

June 26 – Egypt's Ptolemy I Soter abdicates. He is succeeded by his youngest son by his wife Berenice, Ptolemy II Philadelphus, who has been co-regent for three years.
A 110 metre tall lighthouse on the island of Pharos in Alexandria's harbour is completed and serves as a landmark for ships in the eastern Mediterranean. Built by Sostratus of Cnidus for Ptolemy II of Egypt, it is one of the seven wonders of the ancient world. It is a technological triumph and is the archetype of all lighthouses since. A broad spiral ramp leads to the top, where a fire burns at night.

Demetrius Poliorcetes is deserted by his troops and surrenders to Seleucus at Cilicia, where Seleucus keeps him a prisoner.

Dicaearchus, Greek philosopher, cartographer, geographer, mathematician and author (b. c. 350 BC)
Theophrastus, Greek philosopher, a native of Eressos in Lesbos, the successor of Aristotle in the Peripatetic school (b. c. 370 BC)