[Chapter entitled The Middle Ages]
One mustnt exaggerate the Jewish role in lending. Most Jews had nothing to do with the business, and those who did were typically bit players, making minor loans of grain or cloth for a return in kind. Others werent even really Jews. Already in the 1190s, preachers were complaining about lords who would work hand in glove with Christian moneylenders who claimed they were our Jews - and thus under their special protection.
By the 1100s, most Jewish moneylenders had long since been displaced by Lombards (from Northern Italy) and Cahorsins (from the French town of Cahors, north of Toulouse)) - who established themselves across Western Europe and became notorious rural usurers.
The rise of rural usury was itself a sign of a growing free peasantry (there had been no point in making loans to serfs, since they had nothing to re-possess). It accompanied the rise of commercial farming, urban craft guilds, and the commercial revolution of the Middle Ages, all of which finally brought Western Europe to a level of economic activity comparable to that long since considered normal in other parts of the world. The Church quickly came under considerable popular pressure to do something about the problem, and at first it did try to tighten the clamps. Existing loopholes in the usury laws were systematically closed, particularly the use of mortgages. These latter began as an expedient: as in medieval Islam, those determined to dodge the law could simply present the money, claim to be buying the debtors house or field, and then rent it back to the debtor until the principal was repaid. In the case of a mortgage, the house was in theory not even purchased but pledged as security, but any income from it accrued to the lender.
In the eleventh century, this became a favourite trick of monasteries. In I148, it was made illegal: henceforth, all income was to be subtracted from the principal. Similarly, in 1187, merchants were forbidden to charge higher prices when selling on credit - the Church thereby going much further than any school of Islamic law ever had. In 1179, usury was made a mortal sin, and usurers were excommunicated and denied Christian burial. Before long, new orders of itinerant friars like the Franciscans and Dominicans organized preaching campaigns, travelling from town to town, village to village, threatening moneylenders with the loss of their eternal souls if they did not make restitution to their victims.
All this was echoed by a heady intellectual debate in the newly founded universities, not so much as to whether usury was sinful and illegal, but precisely why. Some argued that it was theft of anothers material possessions; others that it constituted a theft of time, charg- ing others for something that belonged only to God. Some held that it embodied the sin of Sloth [because no physical effort was involved]...