Book by French historians J. Deviosse and J.-A. Rua is dedicated to one of the most famous episodes in the political and military history of the European Middle Ages - the Battle of Poitiers (733) between the Muslim troops of the emir Abd-ar-Rahman and the troops of the ruler of the Frankish kingdom, Charles Martel. On the day of the battle, not just two hostile armies collided, but two civilizations alien to each other, one at sunset, the other at the dawn of its development. The battle and the events associated with it quickly became overgrown with legends, behind which it became difficult to discern the true background of the events. Some made the battle a historical milestone on a global scale, believing that Charles Martel saved Europe from enslavement by the Arabs; others viewed it as an ordinary skirmish. What made the Arabs, Berbers and Franks fight to the death on a field near Poitiers in October 733—a holy war, a simple predatory raid, or a political calculation? In order to answer this question, the authors of the book needed to study not only the battle itself and its vicissitudes, but also the entire history of the existence of both the Arab Caliphate and the Frankish state from the moment of their inception.