Harun Al-Rashid (766-809), was the fifth caliph (786-809) of the Abbasid dynasty of Baghdad.Baghdad, the capital of Harun's realm, became the most flourishing city of the period. Tribute was paid to the caliph by many rulers, and splendid edifices were erected in his honour at enormous cost. 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.