Antony, then in Egypt with Cleopatra, did not respond immediately to the Parthian invasion. Though he left Alexandria for Tyre in early 40 BC, when he learned of the civil war between his wife and Octavian, he was forced to return to Italy with his army to secure his position in Rome rather than defeat the Parthians. Instead, Antony dispatched Publius Ventidius Bassus to check the Parthian advance. Arriving in the East in spring 39 BC, Ventidius surprised Labienus near the Taurus Mountains, claiming victory at the Cilician Gates. Ventidius ordered Labienus executed as a traitor and the formerly rebellious Roman soldiers under his command were reincorporated under Antony's control. He then met a Parthian army at the border between Cilicia and Syria, defeating it and killing a large portion of the Parthian soldiers at the Amanus Pass. Ventidius' actions temporarily halted the Parthian advance and restored Roman authority in the East, forcing Pacorus to abandon his conquests and return to Parthia.