Jewish settlers founded the Ashkenazi Jewish community in the Early (5th to 10th centuries CE) and High Middle Ages (c.1000–1299 CE). The community survived under Charlemagne, but suffered during the Crusades. 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. The Jewish communities of the cities of Mainz, Speyer and Worms became the center of Jewish life during Medieval times. "This was a golden age as area bishops protected the Jews resulting in increased trade and prosperity." The First Crusade began an era of persecution of Jews in Germany. Entire communities, like those of Trier, Worms, Mainz, and Cologne, were murdered. The war upon the Hussite heretics became the signal for renewed persecution of Jews. The end of the 15th century was a period of religious hatred that ascribed to Jews all possible evils. The atrocities of Chmielnicki (1648, in the Ukrainian part of southeastern Poland) and his Cossacks drove the Polish Jews back into western Germany. With Napoleon's fall in 1815, growing nationalism resulted in increasing repression. From August to October 1819, pogroms that came to be known as the Hep-Hep riots took place throughout Germany. During this time, many German states stripped Jews of their civil rights. As a result, many German Jews began to emigrate.