Popular unrest forced Brutus and his brother-in-law, fellow assassin Gaius Cassius Longinus, to leave Rome in April 44. After a complex political realignment, Octavian – Caesar's adoptive son – made himself consul and, with his colleague, passed a law retroactively making Brutus and the other conspirators murderers. This led to a second civil war, in which Antony and Octavian fought the "liberatores" led by Brutus and Cassius. The Caesarians decisively defeated the outnumbered armies of Brutus and Cassius at the two battles at Philippi in October 42. After the defeat, Brutus committed suicide.