Jews (identifiable by the Judenhut they were required to wear) were killed by Christian knights during the First Crusade in France and Germany. French Bible illustration from 1250.
The First Crusade began an era of massacres of Jews in Germany. The wild excitement of Crusading, to which the Germans had been driven by exhortations to take the cross, first broke upon the Jews, the nearest representatives of an execrated opposition faith. Entire communities, like those of Trier, Worms, Mainz, and Cologne, were slain, except where the slayers were anticipated by the deliberate self-destruction of their intended victims. The Jewish community of Speyer was saved by the bishop. About 12,000 Jews are said to have perished in the Rhenish cities alone between May and July 1096. These outbreaks of popular passion during the First Crusade influenced the status of the Jews for the next few centuries, and perhaps beyond. The Christians brought accusations against the Jews to argue that the Jews had deserved their fate. Alleged crimes, like desecration of the host, ritual murder, poisoning of wells, and treason, brought hundreds to the stake and drove thousands into exile. Jews were alleged to have caused the inroads of the Mongols, even though they suffered equally with the Christians. When the Black Death swept over Europe in 1348–49, Christians accused Jews of poisoning wells. In the wake of this accusation, a general slaughter began throughout the empire, which triggered a massive exodus east to Poland. Nonrestrictive government policies and public attitudes towards Jews helped the Jewish immigrants to Poland to form the foundations of what would become the largest Jewish community in Europe.
Courtesy : Wikipedia