Under the caliph al-Ma’mun (reigned 813-833) al-Khwarizmi became a member
of the “House of Wisdom” (Dar al-Hikma), a kind of academy of scientists set up
at Baghdad, probably by Caliph Harun al-Rashid, but owing its preeminence to
the interest of al-Ma’mun, a great patron of learning and scientific investigation.
It was for al-Ma’mun that Al-Khwarizmi composed his astronomical treatise,
and his Algebra also is dedicated to that ruler