Within days of Antony's expulsion, on 7 January 49 BC, the senate reconvened. Under the leadership of Cato and with the tacit support of Pompey, the senate passed a "senatus consultum ultimum", a decree stripping Caesar of his command and ordering him to return to Rome and stand trial for war crimes. The senate further declared Caesar a traitor and a public enemy if he did not immediately disband his army. With all hopes of finding a peaceful solution gone after Antony's expulsion, Caesar used Antony as a pretext for marching on Rome. As tribune, Antony's person was sacrosanct, so it was unlawful to harm him or to refuse to recognize his veto. Three days later, on 10 January, Caesar crossed the Rubicon, initiating the Civil War. During the southern march, Caesar placed Antony as his second in command.