Harun al-Rashid was the fifth caliph of the Abbasid Empire, he ruled during its apogee, as described in The 1001 Nights. Born to the caliph al-Mahdi and the former slave-girl al-Khayzuran, Harun was raised at court and received the bulk of his education from Yahya the Barmakid, who was a loyal supporter of Harun's mother. Harun was named second in line to the throne after his older brother, al-Hadi.
Before he was out of his teens, Harun was made the nominal leader of several expeditions against the Eastern Roman Empire, where his success, or more accurately, the success of his generals, resulted in him earning the title "al-Rashid," "the one following the right path" or "the just." He was also appointed the governor of Armenia, Azerbaijan, Egypt, Syria and Tunisia, which Yahya administered for him.
His father, al-Mahdi, died in 785 and brother al-Hadi died mysteriously in 786, and Harun became caliph in September of that year. He appointed as his vizier Yahya, who installed a cadre of Barmakids as administrators. His mother al-Khayzuran had considerable influence over her son until her death in 803, and the Barmakids effectively ran the empire for Harun. Regional dynasties were given semi-autonomous status in return for considerable annual payments, which enriched Harun financially, but weakened the power of the caliphs. He also divided his empire between his sons al-Amin and al-Ma'mum, who went to war after Harun's death.
Harun was a great patron of art and learning, and is best known for the unsurpassed splendor of his court and lifestyle. Some of the stories, perhaps the earliest of The Thousand and One Nights, were inspired by the glittering Baghdad court, and the character King Shahryar, whose wife Scheherazade tells the tales, may have been based on Harun.
Harun founded with his son and successor al-Ma'mum the Bayt al-Hikmah, House of Wisdom, in Baghdad, where works from classical Greece were translated, studied, and preserved.
Sources: "Harun al-Rashid." Who's Who in the Middle Ages and the Renaissance; Saudi Aramco World, January-February 2002.