When Octavian (later Augustus Caesar), Julius Caesar’s adopted son and heir, arrived in Rome, Marcus Antonius joined forces with him, but they soon fell out. Antony went to take Cisalpine Gaul as his assigned proconsular province, but Decimus Brutus would not give it up, and Antony besieged him (43 B.C.) at Mutina (modern Modena). The senate, urged by Cicero, who had excoriated Antony in the Philippics, sent the consuls Aulus Hirtius and Caius Vibius Pansa to attack Antony. The consuls fell in battle, but Antony retired into Transalpine Gaul. 3 Octavian now decided for peace and arranged with Antony and Marcus Aemilius Lepidus the Second Triumvirate, with Antony receiving Asia as his command. In the proscription following this treaty Antony had Cicero killed. Antony and Octavian crushed the republicans at Philippi, and the triumvirate ruled the empire for five years.