Until the great massacres during the Crusades, they constituted a middle class of merchants, physicians, and other profissionals

"Germany was neither a geographic nor even a clear-cut linguistic entity. There were large, cohesive German-speaking communities in distant Russia, on the banks of the Volga and on the shores of the Black Sea in what are today Ukraine, Moldavia, and Romania. There was as yet no hint of a national consciousness anywhere to unite the speakers of more than a dozen dialects (...)

Jews were by no means newcomers to these regions. No one knows exactly when they first arrived. They seem to have reached the Rhineland and the Danube valley in the wake of Roman legions, long before the establishment of Christianity. In some parts they may have settled earlier than the (later Germanized) Celts, Balts, and Slavs. Long before there were Saxons, Bavarians, or Prussians, Jews lived in what was later known as the Germans lands. A literate community of ancient renown, in the early Middle Ages they constituted an early urban middle class of traders, surgeons, apothecaries, and crafsmen in gold, silver, and precious stones. The earliest written record testifying to their presence in the Rhineland is the text of a decree of A.D. 321 by the emperor Constantine (...). It instructs the Roman magistrate of Cologne on relations with the local rabbi.

During the Christianization of Western Europe, they were the only people who retained their religious faith, sometimes at a high price. The first centuries of Christian rule were, by and large, relatively tolerant. For long periods Jews and Germans coexisted peacefully. Prior to the Crusades, Jews were free to own property and practice all trades and professions. Later, their lives were made miserable by the brutality and superstition of the mob, the greed of princes, and the growing intolerance of the Church. By the fifteenth and sixteenth centuries they had become mostly rag dealers, pawnbrokers, money changers, peddlers, and vagrants. The remarkable thing about them was that the poorest men (and some of the women) were often literate, though in Hebrew only."

                           Amos Elon, The Pity Of It All - A portrait of the German-Jewish Epoch 1743 -1933, Picador, 2002, pp. 20-21