The great scholars of medieval Jewish history (Soloveitchik, Brody, Ta Shma, Berger, Emanuel, and others) are divided as to the origins of the Great and Holy Ashkenazic communities in the 10th and 11th centuries. The balance of opinion currently is that the origins were in Bavel and not Eretz Yisrael. The debate is a lively one, to say the least. Sources upon request.
