Armenia had been constantly the source of war between the Roman and Sasanian Empires. In 378/9, Shapur II had achieved Iranian hegemony over the country after its regent Manuel Mamikonian submitted to him. A force 10,000 of Iranian soldiers led by general Surena were dispatched to Armenia. Surena was given the title of "marzban" (margrave), which indicates that Armenia was now a Sasanian province. Under Ardashir II, however, Manuel rebelled and succeeded in maintaining independence against both the Iranians and Romans in the early 380s. However, just before his death in 385/386, he seemingly placed Armenia under Roman protection. With his death, many Armenian "nakharars" (grandees) revolted against the Arsacid king Arshak III () and appealed to Shapur III for another king. Shapur III responded by crowning Khosrov IV as king, and gave him his sister Zurvandukht in marriage. He then sent an invasion force into Armenia, which occupied most of the country. Arshak III was forced to withdraw to the western region of Acilisene, where he awaited Roman reinforcements.