First conflict with Antony

Bust of Caesar Augustus from the Musei Capitolini, Rome

After Decimus Brutus refused to give up Cisalpine Gaul, Antony besieged him at Mutina. The resolutions passed by the Senate to stop the violence were rejected by Antony, as the Senate had no army of its own to challenge him; this provided an opportunity for Octavian, who was already known to have armed forces. Cicero also defended Octavian against Antony's taunts about Octavian's lack of noble lineage; he stated "we have no more brilliant example of traditional piety among our youth." This was in part a rebuttal to Antony's opinion of Octavian, as Cicero quoted Antony saying to Octavian, "You, boy, owe everything to your name." In this unlikely alliance orchestrated by the arch anti-Caesarian senator Cicero, the Senate inducted Octavian as senator on 1 January 43 BC, yet he was also given the power to vote alongside the former consuls. In addition, Octavian was granted imperium (commanding power), which made his command of troops legal, sending him to relieve the siege along with Hirtius and Pansa (the consuls for 43 BC). In April of 43 BC, Antony's forces were defeated at the battles of Forum Gallorum and Mutina, forcing Antony to retreat to Transalpine Gaul. However, both consuls were killed, leaving Octavian in sole command of their armies.
After heaping many more rewards on Decimus Brutus than Octavian for defeating Antony, the Senate attempted to give command of the consular legions to Decimus Brutus, yet Octavian decided not to cooperate. Instead, Octavian stayed in the Po Valley and refused to aid any further offensive against Antony. In July, an embassy of centurions sent by Octavian entered Rome and demanded that he receive the consulship left vacant by Hirtius and Pansa. Octavian also demanded that the decree declaring Antony a public enemy should be rescinded. When this was refused, he marched on the city with eight legions. He encountered no military opposition in Rome, and on 19 August 43 BC was elected consul with his relative Quintus Pedius as co-consul. Meanwhile, Antony formed an alliance with Marcus Aemilius Lepidus, another leading Caesarian.

Bust of Caesar Augustus from the Musei Capitolini, Rome

After Decimus Brutus refused to give up Cisalpine Gaul, Antony besieged him at Mutina. The resolutions passed by the Senate to stop the violence were rejected by Antony, as the Senate had no army of its own to challenge him; this provided an opportunity for Octavian, who was already known to have armed forces. Cicero also defended Octavian against Antony's taunts about Octavian's lack of noble lineage; he stated "we have no more brilliant example of traditional piety among our youth." This was in part a rebuttal to Antony's opinion of Octavian, as Cicero quoted Antony saying to Octavian, "You, boy, owe everything to your name." In this unlikely alliance orchestrated by the arch anti-Caesarian senator Cicero, the Senate inducted Octavian as senator on 1 January 43 BC, yet he was also given the power to vote alongside the former consuls. In addition, Octavian was granted imperium (commanding power), which made his command of troops legal, sending him to relieve the siege along with Hirtius and Pansa (the consuls for 43 BC). In April of 43 BC, Antony's forces were defeated at the battles of Forum Gallorum and Mutina, forcing Antony to retreat to Transalpine Gaul. However, both consuls were killed, leaving Octavian in sole command of their armies.
After heaping many more rewards on Decimus Brutus than Octavian for defeating Antony, the Senate attempted to give command of the consular legions to Decimus Brutus, yet Octavian decided not to cooperate. Instead, Octavian stayed in the Po Valley and refused to aid any further offensive against Antony. In July, an embassy of centurions sent by Octavian entered Rome and demanded that he receive the consulship left vacant by Hirtius and Pansa. Octavian also demanded that the decree declaring Antony a public enemy should be rescinded. When this was refused, he marched on the city with eight legions. He encountered no military opposition in Rome, and on 19 August 43 BC was elected consul with his relative Quintus Pedius as co-consul. Meanwhile, Antony formed an alliance with Marcus Aemilius Lepidus, another leading Caesarian.