Pirenne - Mohammed and Charlemagne
Found the Book on scribd and decided to bumb the post. The images are High-res so I would recommend use of the download link
From Wikipedia on the Piranne-thesis: Got to say, that my gut tells me Henri might be on to something
Henri Pirenne first expressed ideas on the formation of European towns in articles of 1895; he further 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 expositions appear in Medieval Cities: Their Origins and the Revival of Trade (1927, based on a series of lectures of 1922),and in his posthumous Mohammed and Charlemagne (1937)..
In brief, Pirenne's Thesis notes that in the ninth century long-distance trading was at a low ebb; the only settlements that were not purely agricultural were the ecclesiastical, military and administrative centres that served the feudal ruling classes as fortresses, episcopal seats, abbeys and occasional royal residences of the peripatetic palatium. When trade revived in the late tenth and eleventh centuries, merchants and artisans were drawn to the existing centres, forming a suburb in which trade and manufactures were concentrated. These were "new men" outside the feudal structure, living on the peripheries of the established order. The feudal core remained static and inert; a time came when the developing merchant class was strong enough to throw off feudal obligations or bought out the prerogatives of the old order, which Pirenne contrasted with the new element in numerous ways. The leaders among the mercantile class formed a bourgeois patriciate, in whose hands economic and political power came to be concentrated.
Pirenne's thesis takes as axiomatic that the natural interests of the feudal nobility and of the urban patriciate, which came to well-attested frictions in the thirteenth and fourteenth centuries, were in their origins incompatible. This aspect of his thesis has been challenged in detail.
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.