Henri Pirenne (December 23, 1862, Verviers - October 25, 1935, Uccle) was a leading Belgian historian. He also became prominent in the non-violent resistance to the Germans who occupied Belgium in World War I.
Henri Pirenne's reputation today rests on three contributions to European history:
Henri Pirenne first developed the idea for the Pirenne Thesis in POW camp during World War I. He subsequently published it in a series of papers from 1922 to 1923 and spent the rest of his life refining the thesis with supporting evidence. The most famous exposition appears in his book Mohammed and Charlemagne (The Birth of the Occident, The Fall of the Antiquity, and the Rise of the Germanic Middle Ages) first published in 1937 (1939 in English).
Traditionally, historians have dated the Middle Ages from the fall of the Roman Empire in the 5th century, a theory Edward Gibbon famously put forward in the 18th century. Pirenne challenged the notion that Germanic barbarians had caused the Roman Empire to end, and he challenged the notion that the end of the Roman Empire should equate with the end of the office of Emperor in Europe, which occurred in 476. He pointed out the essential continuity of the economy of the Roman Mediterranean even after the barbarian invasions, that the Roman way of doing things did not fundamentally change in the time immediately after the "fall" of Rome. Barbarians came to Rome not to destroy it, but to take part in its benefits; they tried to preserve the Roman way of life.
According to Pirenne the real break in Roman history occurred in the 7th century as a result of Arab expansion. Islamic conquest of the area of today's south-eastern Turkey, Syria, Palestine, North Africa, Spain and Portugal ruptured economic ties to Europe, cutting the continent off from trade and turning it into a stagnant backwater, with wealth flowing out in the form of raw resources and nothing coming back. This began a steady decline and impoverishment so that by the time of Charlemagne Europe had become entirely agrarian at a subsistence level, with no long-distance trade. Pirenne says "Without Islam, the Frankish Empire would have probably never existed, and Charlemagne, without Muhammad, would be inconceivable".
Pirenne used quantitative methods in relation to currency in support of his thesis. Much of his argument builds upon the disappearance of items from Europe, items that had to come from outside Europe. For example, the minting of gold coins north of the Alps stopped after the 7th century, indicating a loss of access to wealthier parts of the world. Papyrus, made only in Egypt, no longer appeared north of the Alps after the 7th century: writing reverted to using animal skins, indicating an isolation from wealthier areas.
Pirenne's Thesis has not entirely convinced all historians of the period. One does not have to entirely accept or deny his theory. It has provided useful tools for understanding the period of the Early Middle Ages, and a valuable example of how periodization schemes are provisional, never axiomatic.
Pirenne's other major idea concerned the nature of medieval Belgium. Belgium as an independent nation state had appeared only a generation before Pirenne's birth; throughout Western history, its fortunes had been tied up with the Low Countries, which now include the Netherlands, Luxembourg and parts of north-east France. Furthermore, Belgium lies athwart the great linguistic divide between French and Dutch. The unity of the country might appear accidental, something which Pirenne sought to disprove in his History of Belgium (1899 - 1932). His ideas here have also proved controversial, with many historians preferring to stress the economic unity of the Low Countries as a whole. Henri Pirenne donated the majority of his personal library to the Academia Belgica in Rome. In 1933, he was awarded the Francqui Prize on Human Sciences.
Pirenne is also the author of Medieval Cities: Their Origins and the Revival of Trade (1927), a book based on lectures he delivered in the United States in 1922. In this book he contends that through the period from the tenth to the twelfth centuries, Europe reclaimed control of the Mediterranean from the Moslem world, and opened up sea routes to the Orient. This allowed the formation of a merchant/middle class, and the development of that classes characteristic abode, the city.