After Octavian's return to Rome, he and his supporters realised 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.