After the assassination of Julius Caesar in 44 BC, the assassins, led by Brutus and Cassius, also fled east. Caesar's former lieutenant, Mark Antony passed a law requiring the governor, Quintus Hortensius Hortalus to hand the province over to Antony. Instead, he chose to place the province under Brutus' control - a move that was recognised by the Senate in 43 BC. This led Mark Antony to ally with Octavian in the Second Triumvirate and invade Macedonia, defeating Brutus and his forces at the Battle of Philippi in 42 BC.