Accusations of well poisoning during the Black Death (1346–53) led to mass slaughter of German Jews and their fleeing in large numbers to Poland (Benedictow 393-394). The Jewish communities (Benedictow 393-394) in the cities of Mainz, Speyer and Worms became the center of Jewish life during medieval times (History of Jews in Germany). "This was a golden age as area bishops protected the Jews resulting in increased trade and prosperity (History of Jews in Germany). The First Crusade began an era of persecution of Jews in Germany (Riley-Smith 1991). Entire communities, like those of Trier, Worms, Mainz, and Cologne, were murdered (History of Jews in Germany). During the war on the Hussite, heresy became the signal for the slaughter of the unbelievers (Riley-Smith 1991). The end of the 15th century was a period of religious hatred that ascribed to Jews all possible evils. The atrocities of Chmielnicki, in the Ukrainian part of southeastern Poland) and his Cossacks drove the Polish Jews back into western Germany (History of Jews in Germany). With Napoleon's fall in 1815, growing nationalism resulted in increasing