2017 Reprint of 1939 Edition.  Full facsimile of the original edition, not reproduced with Optical Recognition software.  Henri Pirenne's classic history of Europe between the fifth and ninth centuries, Mohammed and Charlemagne, although published on the eve of the Second World War, remains an important work to this day.  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.