Al-Fadl ibn Sahl

Abu l-Abbas al-Fadl ibn Sahl ibn Zadhanfarukh al-Sarakhsi (Arabic: أبو العباس الفضل بن سهل بن زادانفروخ السرخسي, romanized: Abu’l-ʿAbbās al-Faḍl ibn Sahl ibn Zādānfarrūkh as-Sarakhsī; died 818), titled Dhu 'l-Ri'āsatayn (Arabic: ذُو الرَّياسَتَيْن, "the man of the two headships"), was a famous Persianvizier of the Abbasid era in Khurasan, who served under Caliph al-Ma'mun (r. 813–832). He played a crucial role in the civil war between al-Ma'mun and his brother al-Amin (r. 809–813), and was the vizier of the Abbasid Caliphate until 817.