Al-Fadl ibn Sahl

Abu l-Abbas al-Fadl ibn Sahl ibn Zadhanfarukh al-Sarakhsi, titled Dhu 'l-Ri'āsatayn, was a famous Persian vizier of the Abbasid era in Khurasan, who served under Caliph al-Ma'mun. He played a crucial role in the civil war between al-Ma'mun and his brother al-Amin, and was the vizier of the Abbasid Caliphate until 817.