The province was formed in 363 after the 2nd Peace of Nisibis, composed of the concessions made by Roman Emperor Jovian, which encompassed all Roman territory east of the Tigris that had been ceded by the Sasanians in the 1st Peace of Nisibis in 299.[4] This included the former Armenian provinces of Corduene, Zabdicene, Arzanene and Moxoene as well as Nisibis and Singara. As part of the treaty, the Romans were allowed to evacuate the inhabitants of the cities of Nisibis and Singara,[5] and this led to the mass exodus of the entire populations of both cities to Roman territories to avoid imprisonment and deportation by the Sasanians.[6][7] This also caused the Christian School of Nisibis to move to Edessa. In the 360s, Shapur II divided the office of marzban between his brothers Zamasp and Adurfrazgird and they were granted responsibility for the northern and southern halves of the province respectively.[8]