How did an obscure Islamic visionary found an empire? The Almohad Empire at its zenith in the 12th century was the major power in the Mediterranean and North Africa, ruling a huge region from the Atlas Mountains to Andalusia. Effective administration was backed by military force, and the empire was the seat of a 12th-century renaissance in the fortunes of Islamic power in North Africa and the western Muslim world. The effect on the culture of both the Middle East and Europe was to prove lasting.

Allen Fromherz, drawing on medieval Arabic and Berber sources, analyses the myth and history surrounding the rise of the Almohad Empire. He shows how Muhammad Ibn Tumart, the son of a minor Berber tribal chief, set off on his mission to reform Islam, then at a low point in its history, battered by the crusades, having lost Jerusalem and been undermined by weak spiritual and political leadership. Muhammad Ibn Tumart was proclaimed Mahdi – one who would herald the golden age of Islam – provided charismatic leadership, unwavering adherence to a fundamentalist monotheistic Islam enforced by holy war, established tribal unity, effective administration and a formidable military force. Here were the sinews of the empire's power and the base for lasting political and cultural influence in the Middle East and Europe.