It is not known whether Agrippa fought against his brother in Africa, but he probably served in Caesar's campaign of 46 to 45 BC against Gnaeus Pompeius, which culminated in the Battle of Munda. Caesar regarded him highly enough to send him with Octavius in 45 BC to study in Apollonia (on the Illyrian coast) with the Macedonian legions, while Caesar consolidated his power in Rome. In the fourth month of their stay in Apollonia the news of Julius Caesar's assassination in March 44 BC reached them. Agrippa and another friend, Quintus Salvidienus Rufus, advised Octavius to march on Rome with the troops from Macedonia, but Octavius decided to sail to Italy with a small retinue. After his arrival, he learned that Caesar had adopted him as his legal heir. Octavius at this time took Caesar's name, but modern historians refer to him as "Octavian" during this period.