Al-Ma'mun
Abū Al-Abbas Abdullāh al-Maʾmūn ibn Harūn (also spelled Almamon, Al-Maymun, Al-Ma’moon, and el-Mâmoûn; 13 September 786 – 9 August 833) was an Abbasid caliph. He reigned from 813 until his death in 833.