Al-Husayn was a mawla ("client"), being described as "mawla amir al-mu'minin" and "mawla Abi Ja'far al-Mansur."[1] During the caliphate of Harun al-Rashid (r. 786–809) he appears to have been appointed as governor of Basra at an unspecified date.[2] In 806 he was appointed over Egypt, arriving in the province in July of that year. Initially his mandate was limited to matters of prayers and security (salah) but at a later date he was granted control over the provincial finances (kharaj) as well.[3]