Roman Syria was an early Roman province annexed to the Roman Republic in 64 BC by Pompey in the Third Mithridatic War following the defeat of King of Armenia Tigranes the Great, who had become the protector of the Hellenistic kingdom of Syria. Following the partition of the Herodian Kingdom of Judea into a tetrarchy in 4 BC, it was gradually absorbed into Roman provinces, with Roman Syria annexing Iturea and Trachonitis. Provincia Syria Syria was annexed to the Roman Republic in 64 BC, when Pompey the Great had the Seleucid king Antiochus XIII Asiaticus executed and deposed his successor Philip II Philoromaeus. Pompey appointed Marcus Aemilius Scaurus to the post of Proconsul of Syria. Following the fall of the Roman Republic and its transformation into the Roman Empire, Syria became a Roman imperial province, governed by a Legate. During the early empire, the Roman army in Syria accounted for three legions with auxiliaries who defended the border with Parthia. In 6 AD, Emperor Augustus deposed the ethnarch Herod Archelaus and united Judea, Samaria and Idumea into the Roman province of Judea; such province was placed under the direct authority of the Legate of Syria Publius Sulpicius Quirinius, who appointed Coponius as Prefect of Judea. Following the death of Herod Philip II (34 AD) and the removal of Herod Antipas (39 AD) Ituraea, Trachonitis, Galilee and Perea were also transferred under the jurisdiction of the province of Syria. From 37 to 41 AD, much of Palestine was separated from Syria and transformed into a client kingdom under Herod Agrippa I. After Agrippa's death, his kingdom was gradually re-absorbed into the Roman Empire, until it was officially transformed into a Roman province following the death of Herod Agrippa II. Syrian province forces were directly engaged in the First Jewish–Roman War of 66–70 AD. In 66 AD, Cestius Gallus, legate of Syria, brought the Syrian army, based on Legio XII Fulminata, reinforced by auxiliary troops, to restore order in Judaea and quell the revolt. The legion, however, was ambushed and destroyed by Jewish rebels at the Battle of Beth Horon, a result that shocked the Roman leadership. The future emperor Vespasian was then put in charge of subduing the Jewish revolt. In the summer of 69, Vespasian, with the Syrian units supporting him, launched his bid to become Roman emperor. He defeated his rival Vitellius and ruled as emperor for ten years