marched on Mithridates VI and forced their former king to take his own life in 63 BC. Pharnaces II quickly sent an embassy to Pompey with offers of submission. Pompey accepted Pharnaces II's submission and, in returned, named Pharnaces II as the Roman client king of the Bosporan Kingdom. With Mithridates VI absent from Asia Minor, Pompey officially annexed Bithynia, Pontus, and Cilicia in the Roman Republic as provinces. Invading Armenia in 64 BC, Tigranes surrendered to Pompey and become a client kingdom of Rome. With Armenia reduced, Pompey then traveled south and officially annexed the Roman client kingdom of Syria in the Republic as a province by deposing its king Antiochus XIII Asiaticus. Following the death of Ariobarzanes I, Pompey, as one of his final acts in the East before returning to Rome, installed his son Ariobarzanes II as the new Roman client king of Cappadocia. Ariobarzanes II reigned as Rome's client king until 51 BC when he was assassinated by forces loyal to the neighboring Parthian Empire. The Roman Senate declared his son Ariobarzanes III as his rightful successor and, with military backing from the Roman governor of Cilicia Marcus Tullius Cicero, installed him upon the Cappadocian throne. In 50 BC, Ariobarzanes III, aided by Cicero, discovered a plot by Athenais Philostorgos II, Ariobarzanes III's mother, to depose him and install his younger brother Ariarathes X as king. Together, Cicero and Ariobarzanes III banished Athenais, who was a daughter of Mithridates VI, from Cappadocia. Roman civil wars Cappadocia became an important player during the Roman Republican civil wars. When Julius Caesar crossed the Rubicon River in 49 BC and started his civil war, many members of the Roman Senate under the leadership of Pompey fled to the East. Cappadocian King Ariobarzanes III initially supported Pompey against Caesar, thankful for Pompey's support of his father years earlier. However, following Caesar's victory over Pompey at the Battle of Pharsulus and Pompey's subsequent assassination in 48 BC, Ariobarzanes III declared his loyalty to Caesar. Caesar subsequently named Gnaeus Domitius Calvinus as Roman governor of Asia to act as his chief lieutenant in Asia Minor while he traveled to Ptolemaic Egypt. With the Romans were distracted by civil war, Pharnaces II, the Roman client king of the Bosporan Kingdom and the youngest son of Mithridates VI, decided to seize the opportunity and conquered Colchis and Lesser Armenia (territories of the Roman province