When the Roman general, Lucullus, was pursuing
Mithridates, who had taken refuge in the territory of Tigranes, Magadates went with his army to Tigranes' assistance. Thereupon Antiochus, the son of Antiochus Pius, entered Syria clandestinely and assumed the government with the consent of the people. Nor did Lucullus, who first made war on Tigranes and wrested his newly acquired territory from him, object to Antiochus exercising his ancestral
authority. But Pompey, the successor of Lucullus,
when he had overthrown Mithridates, allowed Tigranes to reign in Armenia and expelled Antiochus from the government of Syria, although he had done the Romans no wrong. The real reason for this was that it was easy for Pompey, with an army under his command, to rob an unarmed king, but the pretence was that it was unseemly for the Seleucidæ, whom Tigranes had dethroned, to govern Syria, rather than the Romans who had conquered Tigranes.