Al-Ma'mun

Abbasid Caliph from 813 to 833

Abu al-Abbas Abd Allah ibn Harun (Arabic: أبو العباس عبد الله بن هارون الرشيد, romanized: Abū al-ʿAbbās ʿAbd Allāh ibn Hārūn ar-Rashīd; 14 September 786 – 9 August 833), better known by his regnal name al-Ma'mun (Arabic: المأمون, lit. 'the Reliable'), was the seventh Abbasid caliph, who reigned from 813 until his death in 833. His leadership was marked by the power and prosperity of the Abbasid Caliphate; al-Ma'mun promoted the Graeco-Arabic translation movement, the flowering of learning and the sciences in Baghdad, and the publishing of al-Khwarizmi's book now known as "Algebra", making al-Ma'mun one of the most important caliphs in the Islamic Golden Age. He is also known as a proponent of the rational Islamic theology of Mu'tazilism.

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