</ref> After the Liberators' defeat, the Parthians invaded Roman territory in 40 BC in conjunction with the Roman Quintus Labienus, a former supporter of Brutus and Cassius. They swiftly overran the Roman province of Syria and advanced into Judea, overthrowing the Roman client Hyrcanus II and installing his nephew Antigonus. For a moment, the whole of the Roman East seemed lost to the Parthians or about to fall into their hands. However, the conclusion of the second Roman civil war soon revived Roman strength in Asia. Mark Antony had sent Ventidius to oppose Labienus, who had invaded Anatolia. Soon Labienus was driven back to Syria by Roman forces, and, although reinforced by the Parthians, was defeated, taken prisoner, and killed. After suffering a further defeat near the Syrian Gates, the Parthians withdrew from Syria. They returned in 38 BC but were decisively defeated by Ventidius, and Pacorus was killed. In Judaea, Antigonus was ousted with Roman help by Herod in 37 BC.* Bivar (1993), 57–58