The present volume of al-Ṭabarī's monumental history covers the years 255-265/869-878, the first half of the reign of the Abbasid caliph al-Muʿtamid in Sāmarrā. Although the decade was one of relative calm in the capital, compared with the anarchy of the years immediately preceding, danger signals were flashing in territories adjacent to the imperial heartlands. Chief among them was the revolt of the Zanj, the narrative of which occupies the bulk of the present volume.

A people of semi-servile status, the Zanj, who were based in the marshlands of southern Iraq, were led by a somewhat shadowy and mysterious figure claiming Shi'ite descent, 'Ali b. Muhammad. Their prolonged revolt against the central authorities was not crushed until 269/882.

Al-Ṭabarī's account of these momentous events is unique in both the quality and the quantity of his information. He himself was present in Baghdad during the years of the revolt, and he was thus able to construct his story from reports by numerous eyewitnesses. The result is a detailed narrative that brings alive for the modern reader the main personalities and engagements of the revolt.