Mohammed and Charlemagne (French: Mahomet et Charlemagne) is an academic book by the Belgian historian Henri Pirenne which was first published posthumously in 1937. It set out an alternative argument about the end of Roman influence in Europe and the emergence of the Dark Ages which emphasised the importance of the Arab expansion in the Middle East and Levant which has become known as the Pirenne Thesis. Although successive historians have tended to reject the argument as an explanation of the period, it remains influential as a means of thinking about geography and periodisation in the Early Middle Ages and the debate it sparked is widely taught in university medieval history courses.