April 14 - Battle of Forum Gallorum: Mark Antony, besieging Caesar's assassin Decimus Brutus in Mutina, defeats the forces of the consul Pansa, but is then immediately defeated by the army of the other consul, Hirtius.
April 21 - Antony is again defeated in the Battle of Mutina by a coalition of Octavian, Decimus Brutus, and the two consuls of the year. Antony withdraws into Transalpine Gaul (France).
July-August – Antony is again at the head of a large army, and Octavian enters Rome in force without opposition. It is clear that Cicero’s plan to divide them against each other has failed.
November - Octavian meets Antony and Lepidus in Bononia, and the three enter into an official five-year autocratic pact, the Second Triumvirate.
