Fifth Abbasid caliph, known to posterity from the Arabian Nights. He came to the throne on the death of his brother, al-Hadi, with the help of the influential Barmakid family, which he permitted to dominate his early reign, but gradually removed from power. He was a great patron of the arts, enthusiastic in waging war against the Byzantines, but less interested in the detail of central government. He weakened the empire through his attempts to divide it among his three sons.
