Battle of Mutina The Battle of Mutina was fought on April 21 , 43 BC between the forces of Mark Antony and the forces of Gaius Vibius Pansa Caetronianus and Aulus Hirtius , who were providing aid to Decimus Junius Brutus Albinus . Prelude . Around one year after Julius Caesar ' s murder , negotiations between the Roman Senate and Antony broke off . Antony gathered his legions and marched against one of the assassins Decimus Junius Brutus Albinus , who was governor of Cisalpine Gaul . Mark Antony had Decimus Brutus confined around " Mutina " ( modern Modena ) , just south of the Padus ( Po ) River on the Via Aemilia . Pansa was sent north from Rome to link with Hirtius and Octavian in order to provide Brutus with aid . On April 14 , Antony marched with his praetorian cohort , the II and the XXXV legion s , light - armed troops and a strong body of cavalry to cut off Pansa before he could reach the senatorial armies . Antony assumed Pansa had only four legions of recruits , but the previous night Hirtius had dispatched the Martian legion and Octavian ' s praetorian cohort to assist Pansa . Antony ' s legions collided with those of Pansa , in the village of Forum Gallorum . In the ensuing Battle of Forum Gallorum , Pansa ' s troops were routed and the general mortally wounded . However , instead of gaining a decisive victory , Antony was forced to withdraw when reinforcements under Hirtius crashed into his own exhausted ranks . The battle . Six days after Forum Gallorum , the two armies met again in the vicinity of Mutina . Octavian ' s forces were now present and fought on the side of the remaining consul Hirtius . Although Antony was defeated , Hirtius himself was killed in the attack on Antony ' s camp . In a result of leaving the army and republic leaderless . Octavian recovered his body and according to Suetonius , " in the thick of the fight , when the eagle - bearer of his legion was sorely wounded , he shouldered the eagle and carried it for some time . " And now with a pro - praetorian imperium , he gained the deceased consul ' s legions . Consequences . Mutina is essentially where Octavian turns from an inferior young man to an equal of Antony . After retreating over the Alps with the remains of his army , Antony soon recrossed the Alps having gathered an army of 17 legions and 10 , 000 cavalry ( in addition to six legions left behind with Varius , according to Plutarch ) . However , soon after the battle , a truce was formed between Antony and Octavian at Bologna leading eventually to the Second Triumvirate with Marcus Aemilius Lepidus , Octavian and Mark Antony . They would set aside their differences and turn on the Senators involved in Caesar ' s assassination while assuming a 3 - way dictatorship . Eventually in the ensuing power struggles many years later , Octavian would defeat Antony and Cleopatra at Actium in 31 BC and usher in the Principate , but Mutina was the milestone where Octavian first established himself as a force to be reckoned with . Without this victory , Octavian might never have achieved the prestige necessary to be looked upon as Caesar ' s successor , and the stability of the Empire might never have been established in the lasting manner which Octavian had decided for it .