He was a member of the Shayban tribe from the Jazira, but otherwise not even the exact name of his father is known, it being variously given as al-Shaykh, Ahmad or Abd al-Razzak.[1] Isa first appears in 848, in the ranks of the Abbasid army under Bugha al-Sharabi that was sent against the rebel Muhammad ibn al-Ba'ith in his stronghold of Marand. Muhammad and most of his followers belonged to the Rabi'a tribal group, the same that the Shayban were part of. Consequently Bugha employed Isa as an envoy to the rebels, and Isa managed to convince several among them to surrender.[1][2]