The belief that the Jews were responsible for the Black Death first took root in southern France and neighboring Spain. In the fourteenth century there were only 2.5 million Jews in all of Europe, but a third of these lived in Spain and on the other side of the Pyrenees in southern France. The Jewish communities in this region were of long standing, in some parts going back to Roman times. There were relatively affluent, extremely literate, and in a relationship of growing tension with their Christian neighbors for both religious and economic reasons....SOURCE: In the Wake of the Plague: The Black Death & the World It Made, by Norman F. Cantor (Harper Perennial, 2002), pp. 150-151, 163-165
The Black Death pogroms against the German Jews had the inevitable effect of making them feel frightened and insecure. When Duke Casimir II of Poland not only tried to protect Jews in his domains from pogroms, but invited Jews to move eastward and settle in his vast, underpopulated domains, large numbers of Jews began to move en masse to Poland.
This immigration continued into the sixteenth century. Like many Western European rulers of the early Middle Ages (700-1000), the Polish duke and his successors saw the Jews as an economic asset, bringing credit facilities and long-distance trade to the country.
By 1500 the Jews had been assigned an additional role of importance in Polish society and the frontier Ukrainian lands also ruled by the Polish nobility. They were widely employed as estate agents for the Polish nobility, supervising thousands of peasants forced into serfdom and managing the exploitation of the rich Polish and Ukrainian soil. Jewish males became trilingual--Hebrew for liturgy and rabbinical learning, a Slavic language for business, and Yiddish, a late medieval German dialect written in Hebrew characters, for everyday life in their own communities (most Jewish women knew only Yiddish).
By the mid-sixteenth-century Jews were rewarded for their services. as estate agents with a lucrative monopoly in selling liquor to the peasants. This is the origin of the Yiddish folk song "a Gentile is a drunkard." Jews also prospered as lumber and fur merchants. Great schools of rabbinical learning, many still in existence when night descended in September 1939, emerged in Poland and the Ukraine. By the early seventeenth century half of the Jewish world population of 3.5 million lived in Poland and the Ukraine.
The Jews came to love the Polish and Ukrainian physical environment and in the nineteenth century (if not much earlier) wrote poetry lavishly praising the farmland, forests, and climate of Eastern Europe. The rise of the great Jewish communities in Slavic Europe, remarkable for their enterprise and traditional learning, and also innovative in religious and literary expression, was a direct result of the Black Death.