Dee ihe na-aga n'ihu maka paragraf a - Abu l-Abbas al-Fadl ibn Sahl ibn Zadhanfarukh al-Sarakhsi (; nwụrụ 818), nke akpọrọ Dhu 'l-Ri'āsatayn ("nwoke nke isi abụọ"), bụ onye ama ama ama ama ama ama ama ama ama ama ama ama nke oge Abbasid na Khurasan, onye jere ozi n'okpuru Caliph al-Ma'mun (r. 813 <unk> 832). O keere òkè dị mkpa n'agha obodo
n'etiti al-Ma'mun na nwanne ya nwoke al-Amin (r. 809<unk>813), ma bụrụ onye isi nke Abbasid Caliphate ruo 817.