Major Events
- Jan 1 The Julian calendar takes effect for the first time, by edict of Roman consul Julius Caesar
- Mar 17 In his last victory, Julius Caesar defeats the Pompeian forces of Titus Labienus and Pompey the Younger in the Battle of Munda
Who Died in 45 BC
- Mar 17 Titus Labienus, Roman leader (Lieutenant of Julius Caesar who later opposed him), killed in the Battle of Munda
- Apr 12 Gnaeus Pompeius, the Younger, Roman general