The history of the Jews in Germany goes back at least to the year 321, and continued through the Early Middle Ages (5th to 10th centuries CE) and High Middle Ages (circa 1000–1299 CE) when Jewish immigrants founded the Ashkenazi Jewish community. 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 they fled 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 slaughtered. The Hussite Wars 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. 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. From the time of Moses Mendelssohn until the 20th century, the community gradually achieved emancipation, and then prospered. In January 1933, some 522,000 Jews lived in Germany. After the Nazis took power and implemented their antisemitic ideology and policies, the Jewish community was increasingly persecuted. About 60% (numbering around 304,000) emigrated during the first six years of the Nazi dictatorship. In 1933, persecution of the Jews became an official Nazi policy. In 1935 and 1936, the pace of antisemitic persecution increased. In 1936, Jews were banned from all professional jobs, effectively preventing them from participating in education, politics, higher education and industry.