The Pirenne thesis was propounded by Belgian historian Henri Pirenne. In his famous essay on Mohammed and Charlemagne (1937) Pirenne argued that the continuity of Roman civilization in transalpine (northern) Europe after the fall of Rome, created real change in Europe came from the rise of Islam, not barbarian invasions. His famous summary said, "Without Islam, the Frankish Empire would have probably never existed, and Charlemagne, without Muhammad, would be inconceivable." That is, he rejected the notion that barbarian invasions in the 4th and 5th centuries caused the collapse of the Roman Empire. Instead the Muslim conquest of north Africa made the Mediterranean a barrier, cutting western Europe off from the east, enabling the Carolingians, especially Charlemagne to create a new, distinctly western form of government.
- Brown, Peter. "Mohammed and Charlemagne by Henri Pirenne." Daedalus 1974 103(1): 25-33. Issn: 0011-5266
- Frank, Kenneth W. "Pirenne Again: A Muslim Viewpoint," The History Teacher, Vol. 26, No. 3 (May, 1993), pp. 371-383 in JSTOR
- Havighurst, Alfred F. ed. The Pirenne Thesis: Analysis, Criticism, and Revision (1958) readings by scholars
- Hodges, Richard, and David Whitehouse. Mohammed, Charlemagne, and the Origins of Europe: Archaeology and the Pirenne Thesis (1983).
- Pirenne, Henri. Medieval Cities: Their Origins and the Revival of Trade (1927) excerpt and text search
- Pirenne, Henri. Mohammed and Charlemagne (1937). onlineedition
- Pirenne, Henri. Economic and Social History of Modern Europe (1936), online edition