After the battle, Mark Antony decided to give up the siege and retreated westward along the via Aemilia, escaping the enemy forces and rejoining the reinforcements of his lieutenant Publius Ventidius Bassus.

Initial news in Rome claimed that the Senate's forces had suffered a defeat at Forum Gallorum, arousing concern and fears among the Republican faction.

In the Senate on 21 April 43 BC, Cicero emphatically pronounced the Fourteenth and final Philippic, in which he exulted in the victory at Forum Gallorum, proposed forty days of public thanksgiving, and particularly praised the legionaries who had fallen and the two consuls Aulus Hirtius and Vibius Pansa.

The orator rather minimized the contribution of Caesar Octavian,[5] although the young man, despite his minor role in the battle, had been acclaimed imperator on the field by the troops, as had the two consuls Hirtius and Pansa.

[7] Mark Antony was by no means resigned to defeat, but for the time being he considered it dangerous to court another pitched battle against combined enemy forces that were numerically superior to his own.

[8] The consul Hirtius and propraetor Octavian, confident after the victory of Forum Gallorum and reassured by the discipline of their Caesarian legions, were determined to force a new struggle to rescue Decimus Brutus and break the siege of Mutina.

[9] After trying unsuccessfully to force Antony into open battle, the two commanders manoeuvred with their troops and concentrated the legions in a field where the enemy camps were less strongly fortified due to the characteristics of the ground.

[8] At the same time, Decimus Brutus had finally organized a sortie with some of his cohorts who, under the command of Lucius Pontius Aquila (another of Caesar's assassins), came out of Mutina and attacked the camp of Antony.

[9] At first, Hirtius' action appeared successful: the Legio III, after breaking through, fought near Antony's tent; the consul led the legionaries on the frontline; meanwhile, the battle continued in other areas as well.

[9] On the basis of the reconstructions of ancient historians it is difficult to know precisely the true course of the final clashes of the battle, with pro-Augustan accounts focused on exalting the role of Octavian and his courageous action to recover the body of the consul Hirtius.

[11] Other sources cast doubts on the real actions of the young heir of Caesar; Suetonius[12] and Tacitus[13] report other versions that hint that Hirtius was even dispatched during the melee by Octavian himself in his eagerness to get rid of an uncomfortable political rival.

He attempted to reach Macedonia, where fellow assassins Marcus Junius Brutus and Gaius Cassius Longinus were stationed, but was captured and executed en route by a Gallic chief loyal to Mark Antony.

[15] However, the very night of the battle, Antony summoned a war council and determined that further resistance would be useless, despite his lieutenants' exhortations that he renew the attack, taking advantage of his superiority in cavalry and the exhaustion of Decimus Brutus's supplies.

[16] He therefore adopted Julius Caesar's expedient after the failure at the Battle of Gergovia and abandoned the siege, hoping to join up with the legions that Ventidius Bassus was bringing from Picenum.

After making his decision, Mark Antony acted swiftly and effectively: the very night after the battle, he sent a message instructing Ventidius Bassus to march quickly through the Apennines and join him with his three legions.

Following the death of Aulus Hirtius in battle on the night of 22–23 April, the consul Vibius Pansa also died as a result of the wounds he had suffered at Forum Gallorum.

In this case, too, the circumstances of his death remained obscure and rumours spread, according to Suetonius and Tacitus, that Pansa had been poisoned, with hints that the ambitious Octavian might be implicated.

Brutus' plans to pursue the enemy were, however, thwarted by the obstructionism of Octavian, who, in command of eight legions at Bononia, did not march to the Apennines to block Ventidius Bassus, as Caesar's assassin had intended.