Fall of Rome – loss of power to tax. Frum,2009 cites Wickham,2009 (cf. Khan, 2009):
As he tells it, the most important dividing line between “ancient” and “medieval” – the profoundest marker of the “fall of Rome” was not a matter of language or culture, of the shift from togas to tunics or from stuffed swan to roast meat. The most important dividing line was the loss of the power and capacity to tax. [...]
After the breakup of the empire, the successor states tried to maintain the old Roman taxes. Some – like the Merovingian Franks – succeeded for a time. But sooner or later, all these tax systems broke down. The world had become too poor, trade and agriculture too unproductive, to yield a positive return on the effort invested in tax collection.
Instead, rulers began assigning lands to their supporters – on the understanding that the supporters and their tenants would follow the ruler to war when summoned. Land assignment was much less efficient than taxation, and the opportunity it presented for treachery was obvious, but as the world narrowed, what other choice was there?
[...] early medieval governments had no taxes or rates to speak of at their disposal. The complex and oppressive system of Roman taxation could not be kept up: already in the late years of the Empire its overburdened subjects sought refuge with the barbarians in order to escape from tax collectors. After the downfall of Imperial rule, all the efforts of barbarian kings to maintain systematic taxation were in vain. They called forth insurrections, and even more powerful was a passive resistance in which all persons concerned joined more or less.
Davies,2002 (3. rev. ed.) (cf.):
CE410; Rome falls to the Visigoths; Banking is abandoned in western Europe and does not develop again until the time of the Crusades. [CE1096]
