The first Jews came into what was then called Germania during the period of the Roman invasion; and, as usual, they came as merchants. During the turmoil caused by the great migrations of the German tribes the Jews seem to have disappeared. We may therefore consider the period when the Germans formed the first political communities as the beginning of that process whereby Central and Northern Europe was again, and this time permanently, Judaized. A development began which has always been the same or similar wherever and whenever Jews came into contact with Aryan peoples.