The most famous Abbasid Caliph whose reign coincided with the zenith of caliphal absolute power, and who presided over a magnificent cultural florescence. Harun al-Rashid succeeded to the Caliphate in 786 and ruled like an absolute monarch with elaborate pomp. Courtiers kissed the ground when they came into his presence. The executioner stood behind him, to show that the Caliph had the power of life and death. The Caliph Harun al-Rashid no longer supervised the affairs of the ummah himself, but left government to his vizier. His role was to be a court of ultimate appeal, beyond the reach of factions and politicking. He led the prayers on Friday afternoons and led his army into major battles. Harun al-Rashid 's caliphate was a political and economic success in these early days. His role was to provide his subjects with security, and the empire enjoyed an unprecedented peace. Uprisings had been ruthlessly quashed, and the populace could see that opposition to this regime was pointless - people were able to live more normal, undisturbed lives. The degree of power and glory attained by al-Harun can be gained from the fact that when the Byzantine King Nicephorus I demanded the return of the tribute already paid, Harun was inflamed with rage and true to his word, captured Hiraqlah and Tyana in 806 and in addition to the tribute, imposed an ignominious tax on the Emperor himself. Caliph Harun Al-Rashid's court was a brilliant centre of learning and art. He was a patron of the arts and scholarship, and inspired a great cultural renaissance. Literary criticism, philosophy, poetry, medicine, mathematics and astronomy flourished not only in Baghdad but also in Kufah, Basrah, Jundayvebar and Harran. Building on the learning of the past, which thus becomes available to them, Muslims scholars made more scientific discoveries during this time than in the whole of previously recorded history. Caliph Harun al-Rashid's rule industry and commerce also flourished, and the elite lived in refinement and luxury. The Caliph and his entourage lived in splendid isolation and far from confining themselves to the four wives prescribed in the Qura'an, they had vast harems. By the end of the reign of Harun al-Rashid, it was clear that the caliphate had passed its peak. No single government could control such vast territory indefinitely. Some of the peripheral provinces, such as Spain (where an escaping Umayyad had set up a rival dynasty in 756) were beginning to break away. The economy was in decline. Harun al-Rashid had tried to solve the problem by dividing the empire between his two sons, but this only resulted in a civil war between the brothers after his death. And after the execution of the Barmaki family (Yahya Barmaki was his grand Vizier) in 803, his affairs fell into confusion, and rebellion broke out. Harun Al-Rashid was born near Tehran, and he died at Tus of an apoplexy.