
Marble bust
The Louvre,
Paris
After Octavian's return to Rome, he and his supporters realized they needed the support of legions.
Agrippa helped Octavian to levy troops in Campania. Once Octavian had his legions, he made a pact with Mark Antony and Lepidus, legally established in 43 BC as the Second Triumvirate. Octavian and his consular colleague Quintus Pedius arranged for Caesar's assassins to be prosecuted in their absence, and Agrippa was entrusted with the case against Gaius Cassius Longinus. It may have been in the same year that Agrippa began his political career, holding the position of Tribune of the Plebs, which granted him entry to the Senate.
In 42 BC, Agrippa probably fought alongside Octavian and Antony in the Battle of Philippi. After their return to Rome, he played a major role in Octavian's war against Lucius Antonius and Fulvia Antonia, respectively the brother and wife of Mark Antony, which began in 41 BC and ended in the capture of Perusia in 40 BC.
However, Salvidienus remained Octavian's main general at this time.
After the Perusine war, Octavian departed for Gaul, leaving Agrippa as urban praetor in Rome with instructions
to defend Italy against Sextus Pompeius, an opponent of the Triumvirate who was now occupying Sicily. In July 40, while Agrippa was occupied with the Ludi Apollinares that were the praetor's responsibility, Sextus began a raid in southern Italy. Agrippa advanced on him, forcing him to withdraw.
However, the Triumvirate proved unstable, and in August 40 Antony sided with Sextus in a joint invasion of Italy. Agrippa's success in retaking Sipontum from Antony helped bring an end to the conflict.
Agrippa was among the intermediaries through whom Antony and Octavian agreed once more upon peace.
During the discussions Octavian learned that Salvidienus had offered to betray him to Antony, with the result
that Salvidienus was executed or committed suicide. Agrippa was now Octavian's leading general.