280 BCCenturies: 4th century BC - 3rd century BC - 2nd century BC
- Battle of Heraclea: The Greeks, led by Pyrrhus of Epirus, defeat with severe casualties a Roman army the first time these cultures meet in battle.
- Aristarchus uses the size of the Earth's shadow on the Moon to estimate that the Moon's radius is one-third that of the Earth.
- Achaean League refounded.
- Philon of Byzantium