285 BC

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

285 BC in various calendars

Gregorian calendar	285 BC CCLXXXV BC
Ab urbe condita	469
Ancient Egypt era	XXXIII dynasty, 39
- Pharaoh	Ptolemy I Soter, 39
Ancient Greek era	123rd Olympiad, year 4
Assyrian calendar	4466
Balinese saka calendar	N/A
Bengali calendar	−877
Berber calendar	666
Buddhist calendar	260
Burmese calendar	−922
Byzantine calendar	5224–5225
Chinese calendar	乙亥年 (Wood Pig) 2413 or 2206     — to — 丙子年 (Fire Rat) 2414 or 2207
Coptic calendar	−568 – −567
Discordian calendar	882
Ethiopian calendar	−292 – −291
Hebrew calendar	3476–3477
Hindu calendars
- Vikram Samvat	−228 – −227
- Shaka Samvat	N/A
- Kali Yuga	2816–2817
Holocene calendar	9716
Iranian calendar	906 BP – 905 BP
Islamic calendar	934 BH – 933 BH
Javanese calendar	N/A
Julian calendar	N/A
Korean calendar	2049
Minguo calendar	2196 before ROC 民前2196年
Nanakshahi calendar	−1752
Seleucid era	27/28 AG
Thai solar calendar	258–259
Tibetan calendar	阴木猪年 (female Wood-Pig) −158 or −539 or −1311     — to — 阳火鼠年 (male Fire-Rat) −157 or −538 or −1310

Year 285 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Canina and Lepidus (or, less frequently, year 469 Ab urbe condita). The denomination 285 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

Egypt

• 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.

Seleucid Empire

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

China

• The success of Qi has frightened the other states. Under the leadership of Lord Mengchang, who has been exiled in Wei, Qin, Zhao, Han and Yan form an alliance. Yan had normally been a relatively weak ally of Qi and Qi feared little from this quarter. Yan's onslaught under general Yue Yi comes as a devastating surprise. Simultaneously, the other allies attack from the west. Chu declares itself an ally of Qi but contents itself with annexing some territory to its north. Qi's armies are destroyed while the territory of Qi is reduced to the two cities of Ju and Jimo. King Min himself is later captured and executed by his own followers.

Deaths

• 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)