1. Al-Ma'mun's 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".
Al-Ma'mun is known as a proponent of the rational Islamic theology of Mu'tazilism.
Al-Ma'mun succeeded his half-brother al-Amin after a civil war, much of his reign was spent on peace campaigns.
Al-Ma'mun was trained in fiqh by al-Hasan al-Lu'lu'i, showing particular excellence in the Hanafi school, and in the hadith, becoming himself active as a transmitter.
Al-Ma'mun was defeated and he quickly abdicated asserting that he had only become caliph on news that al-Ma'mun had died.
Al-Ma'mun moved Imam Reza to Merv in hopes of keeping watch over him, but was foiled by the Imam's growing popularity there.
Al-Ma'mun ordered that the Imam be buried next to the tomb of his own father, Harun al-Rashid, and showed extreme sorrow in the funeral ritual and stayed for three days at the place.
Al-Ma'mun meanwhile launched an invasion of Anatolia in 830 AD, taking a number of Byzantine forts; he spared the surrendering Byzantines.
Al-Ma'mun made preparations for a major campaign, but died on the way while leading an expedition in Tyana.
Al-Ma'mun gathered scholars of many religions at Baghdad, whom he treated magnificently.
Al-Ma'mun sent an emissary to the Byzantine Empire to collect the most famous manuscripts there, and had them translated into Arabic.
Al-Ma'mun introduced the mihna with the intention of centralizing religious power in the caliphal institution and testing the loyalty of his subjects.
Al-Ma'mun was a pioneer of cartography having commissioned a world map from a large group of astronomers and geographers.
Al-Ma'mun had been named governor of Khurasan by Harun, and after his ascension to power, the caliph named Tahir as governor for his military services in order to assure his loyalty.
Al-Ma'mun attempted to divorce his wife during his reign, who had not borne him any children.
Al-Ma'mun's wife hired a Syrian judge of her own before al-Ma'mun was able to select one himself; the judge, who sympathized with the caliph's wife, refused the divorce.
Al-Ma'mun was assisted by several geographer, astronomer and mathematicians from the House of Wisdom.
Al-Ma'mun relates anecdotes concerning the caliph's ability to speak concisely and eloquently without preparation, his generosity, his respect for Muhammad and religion, his sense of moderation, justice, his love of poetry and his insatiable passion for physical intimacy.
Al-Ma'mun was brought by al-Amin, who then sold her to his brother.
Al-Ma'mun was a singer, and had been a slave of Arib.
Al-Ma'mun was an accomplished poet and a native of Basra.
Al-Ma'mun was noted for beauty and elegance, and it was said that al-Ma'mun favoured her above all his other concubines.
Al-Ma'mun was inconsolable at his death and mourned him in many poems.
Al-Ma'mun had been formerly a concubine of his cousin Ja'far bin al-Hadi, his brother al-Amin and Ali bin Hisham.
Al-Ma'mun was a poetess and was one of his favourites.
Al-Ma'mun asked what would go best with this water and was told a specific kind of fresh dates.
Al-Ma'mun encouraged his successor to continue his policies and not burden the people with more than they could bear.
Al-Ma'mun was the last Abbasid caliph who had a one-word Laqab, his successors had laqab with suffixes like Billah or ala Allah.
Al-Ma'mun ordered that al-Ridha be buried next to the tomb of his own father, Harun al-Rashid, and showed extreme sorrow in the funeral ritual and stayed for three days at the place.