305 BCCenturies: 5th century BC - 4th century BC - 3rd century BC
- Siege of Rhodes by Demetrius I of Macedon starts.
- Satrap Lysimachus of Thrace declares himself King.
- Ptolemy, former general of Alexander the Great, names himself King of Egypt and initiates a 20-year reign as Ptolemy I Soter (Savior).
- Seleucus I Nicator, , a former general of Alexander the Great, establishes the Seleucid Empire that rules Babylonia and Syria for two and a half centuries.
- Battle of Bovianum: The Roman consuls M. Fulvius and L. Postumius decisively defeat the Samnites to end the Second Samnite War.