Harun Ar-Rashid was the Fifth Caliph of the Abbasid Dynasty of Baghdad. Ruling from 786 until 809, he succeeded to the throne, at the age of 20, on the death of his brother Al-Hadi. The period of his reign marked a notable development of culture. He is said to have exchanged gifts with Charlemagne. Harun was a generous patron of learning, poetry, and music, and his court was visited by the most eminent Muslims of the age.
He was celebrated in countless songs and stories, and is perhaps best known to the western world as the Caliph whose court is described in the Arabian Nights. The Abbasids were an Arab family descended from Abbas, the uncle of Muhammad. They held the Caliphate from 749 until 1258. They united the country in revolt against the Umayyads in 747, under the First Abbasid Caliph.
The Abbasid Caliph moved the capital from Damascus to Baghdad, and Persian influence grew in the empire. The early years were glorious, rising to true splendor under the Fifth Abbasid Caliph, and to intellectual brilliance under the seventh. All of this took place, however, in less than a hundred years. The remaining 400 plus years of the regime was a long, slow, steady decline. In 1258 one remaining family member escaped to Cairo and was recognized as Caliph, and the family survived there, under the Mamluks, until the Ottoman Conquest of Egypt in 1517.