Whilst trawling for information on foundlings, I stumbled upon this story, which I had heard of, but knew nothing about. This is from The Medieval World Europe 1100-1350 by Frederick Heer:
“The great economic and political power of Italian finance would have been impossible without overseas trade. From the mid-eleventh century the Italian maritime cities had taken over the carrying trade from the Byzantine Empire, whose commercial fleet had fallen into decline, and this gave them control of the commerce of the eastern Mediterranean and of the Near and Far Eastern trade. The trade-routes leading north over the Savoy passes became the special preserve of the traders and financiers of Lombardy and the inland Italian cities. This gave them access to the trade fairs of Champagne, and to the urbanized regions of Northern France, Flanders, and north-western Germany the most important centres of trade and industry north of the Alps. Here the Italians linked up with German merchants, whose trading connections extended as far as Novgorod, and with Englishmen and Scandinavians.
Venice, Genoa and Pisa profited enormously form the Crusades of the 12th and early 13th centuries, when they had the monopoly of transporting and supplying the Western armies. They also succeeded in establishing their right to a third of each of the conquered Syrian towns. Here they built up the ‘earliest European colonial capitalism’, putting their subjects, the majority of them non-Christian, to forced labour in their industrial enterprises. By this means they acquired the monopoly of silk and glass manufacture. The names of fabrics such as damask (from Damascus), muslin (from Mossul) and gauze (from Gaza) recall this golden age of Italian Levantine trade. By the mid-thirteenth century the 2 great rivals, Genoa and Venice, had complete control over their respective spheres of influence, for Genoa the Black Sea ports, for Venice the Greek islands.
Slaves were also an important and constant item of merchandise and slave markets were set up at Venice, Florence and Rome; eminent citizens kept slaves as a matter of course. Lurid light is thrown on the unscrupulous mentality of the Italian traders by the sale into slavery of French and German children, followers of the Children’s Crusades, who landed at Italian ports and were sold off by the shippers to their Muslim business associates.
Slavery came to an end largely for economic reasons – where industry was highly developed it became unprofitable. I was abolished first in the smaller towns, at Pistoia in 1205 and at Assisi in 1210, but in Bologna only in 1256 and in Florence in 1299. Official prohibition, however, at first only brought about a very gradual decline.”
This last sentence is highly significant, as it is claimed by some authors that the Roman Empire deliberately avoided technology in order to continue with slavery. By contrast, the Carthusian monks were highly organised and mechanised in order to allow them more time for their religious practices. The end of the modern European slavery coincided with the rise of the industrial revolution and abolitionists mostly came from non conformists who were often industrialists.