Ma'mun, al-

[ al-mah-moon, -ma- ]
/ ˈæl mɑˈmun, -mæ- /

noun

abu-al-'Abbās 'Abdullāh,a.d. 786–833, caliph of Baghdad 813–833 (son of Harun al-Rashid).
Also al-Mamoun.