the year 321,[2][3] 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[4]

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."[5]