The Islamic world in its year 132 (570 AD) was ruled by a new revolutionary regime. The dynasty that it brought to power was revered as the Imams of the Sunni Muslims for the next 767 years. In good part, this stability and longevity were founded by the remarkable grandfather of Hārūn al-Rashīd, Abū Ja'far al-Mansūr, who came to power in 754 AD and died in 775. Al-Mansūr destroyed every threat to his own supremacy, leaving an opulent autocracy to his son. Here are the reminiscences of those who witnessed these years, woven by the great historiographer al-Tabarī (d. 923) into a vivid account, translated for the first time into a western language from its source, hitherto available to a few specialists. This deft translation gives access to the world of eighth-century Baghdad, but also transcends that time in an account of permanent significance.