 Mithridates' ambitious son-in-law, Tigranes the Great, king of Armenia, however, saw opportunity for expansion in the constant civil strife to the south.In 83 BC, at the invitation of one of the factions in the interminable civil wars, he invaded Syria and soon established himself as ruler of Syria, putting the Seleucid Empire virtually at an end.Seleucid rule was not entirely over, however.