Year 285 BC was a year of the pre-Julian Roman calendar

Roman calendar

The Roman calendar changed its form several times in the time between the founding of Rome and the fall of the Roman Empire. This article generally discusses the early Roman or pre-Julian calendars...

. At the time it was known as the Year of the Consulship of Canina and Lepidus (or, less frequently, year 469 Ab urbe condita

Ab urbe condita

Ab urbe condita is Latin for "from the founding of the City ", traditionally set in 753 BC. AUC is a year-numbering system used by some ancient Roman historians to identify particular Roman years...

). The denomination 285 BC for this year has been used since the early medieval period, when the Anno Domini

Anno Domini

and Before Christ are designations used to label or number years used with the Julian and Gregorian calendars....

 calendar era

Calendar era

A calendar era is the year numbering system used by a calendar. For example, the Gregorian calendar numbers its years in the Western Christian era . The instant, date, or year from which time is marked is called the epoch of the era...

 became the prevalent method in Europe for naming years.

Egypt

• June 26 – Egypt's
  Ancient Egypt
  Ancient Egypt was an ancient civilization of Northeastern Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. Egyptian civilization coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh...
  
   Ptolemy I Soter
  Ptolemy I Soter
  Ptolemy I Soter I , also known as Ptolemy Lagides, c. 367 BC – c. 283 BC, was a Macedonian general under Alexander the Great, who became ruler of Egypt and founder of both the Ptolemaic Kingdom and the Ptolemaic Dynasty...
  
   abdicates. He is succeeded by his youngest son by his wife Berenice
  Berenice I of Egypt
  Berenice I was a Greek Macedonian noblewoman and through her marriage to Ptolemy I Soter, became the first Queen of the Ptolemaic dynasty of Egypt.-Family:...
  
  , Ptolemy II Philadelphus
  Ptolemy II Philadelphus
  Ptolemy II Philadelphus was the king of Ptolemaic Egypt from 283 BCE to 246 BCE. He was the son of the founder of the Ptolemaic kingdom Ptolemy I Soter and Berenice, and was educated by Philitas of Cos...
  
  , who has been co-regent for three years.
• A 110 metre tall lighthouse on the island of Pharos
  Lighthouse of Alexandria
  The Lighthouse of Alexandria, also known as the Pharos of Alexandria , was a tower built between 280 and 247 BC on the island of Pharos at Alexandria, Egypt...
  
   in Alexandria
  Alexandria
  Alexandria is the second-largest city of Egypt, with a population of 4.1 million, extending about along the coast of the Mediterranean Sea in the north central part of the country; it is also the largest city lying directly on the Mediterranean coast. It is Egypt's largest seaport, serving...
  
  's harbour is completed and serves as a landmark for ships in the eastern Mediterranean. Built by Sostratus of Cnidus
  Sostratus of Cnidus
  Sostratus of Cnidus , was a Greek architect and engineer. He designed the lighthouse of Alexandria, one of the Seven Wonders of the World , on the island of Pharos off Alexandria, Egypt.-External links:*...
  
   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
  Seleucus I Nicator
  Seleucus I was a Macedonian officer of Alexander the Great and one of the Diadochi. In the Wars of the Diadochi that took place after Alexander's death, Seleucus established the Seleucid dynasty and the Seleucid Empire...
  
   at Cilicia
  Cilicia
  In antiquity, Cilicia was the south coastal region of Asia Minor, south of the central Anatolian plateau. It existed as a political entity from Hittite times into the Byzantine empire...
  
  , where Seleucus keeps him a prisoner.

Deaths

• Dicaearchus
  Dicaearchus
  Dicaearchus of Messana was a Greek philosopher, cartographer, geographer, mathematician and author. Dicaearchus was Aristotle's student in the Lyceum. Very little of his work remains extant. He wrote on the history and geography of Greece, of which his most important work was his Life of Greece...
  
  , Greek
  Ancient Greece
  Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...
  
   philosopher, cartographer, geographer, mathematician and author (b. c. 350 BC
  350 BC
  Year 350 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Laenas and Scipio...
  
  )
• Theophrastus
  Theophrastus
  Theophrastus , a Greek native of Eresos in Lesbos, was the successor to Aristotle in the Peripatetic school. He came to Athens at a young age, and initially studied in Plato's school. After Plato's death he attached himself to Aristotle. Aristotle bequeathed to Theophrastus his writings, and...
  
  , Greek philosopher, a native of Eressos in Lesbos, the successor of Aristotle
  Aristotle
  Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...
  
   in the Peripatetic school (b. c. 370 BC
  370 BC
  Year 370 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Tribunate of Capitolinus, Medullinus, Praetextatus, Cornelius, Volusus and Poplicola...
  
  )