Abdallah, the future al-Ma'mun, was born in Baghdad on the night of the 13 to 14 September 786 CE to Harun al-Rashid and his concubine Marajil, from Badghis. On the same night, which later became known as the "night of the three See more

In 802 Harun al-Rashid, father of al-Maʾmūn and al-Amin, ordered that al-Amin succeed him, and al-Ma'mun serve as governor of See more

The rebel forces in Baghdad splintered and wavered in opposition to Al-Ma'mun. According to scholar and historian Al-Tabari (839–923 CE), al-Ma'mun entered Baghdad on 11 … See more

Al-Ma'mun conducted, in the plains of Mesopotamia, two astronomical operations intended to achieve a degree measurement (al-Ma'mun's arc measurement). The crater Almanon on the moon is named in recognition of his contributions to … See more

Although Abdallah was the oldest of his sons, in 794 Harun named the second-born Muhammad, born in April 787 to Zubayda, as the first in line of succession. This was the result of family pressure on the Caliph, reflecting Muhammad's higher birth, as both … See more

Sahl ibn Salama al-Ansari
There were disturbances in Iraq during the first several years of al-Maʾmūn's reign, while the caliph was in Merv (near present-day Mary, Turkmenistan). On 13 November 815, Muhammad ibn Ja'far al-Sadiq (Al-Dibaj) claimed … See more

By the time al-Ma'mun became Caliph, the Arabs and the Byzantine Empire had settled down into border skirmishing, with Arab raids deep into Anatolia to capture booty and … See more