The differences between the Jews of the Iberian Peninsula and the Jews from Northern France and Germany are traced to the various social, religious, economic, political, geographic, and even ethnic influences existent in each of these communities. The differences are too numerous to enumerate in any great detail. The variation in practice in Ashkenazi and Sephardi schools of rabbinic thought are also often argued to reflect the differences in Jewish communities originally from Palestinian and Babylonian origin, which served to influence the two former groups.
The Christian reconquest of Europe changed the political and religious environment of Jews in the nation of Spain. While this eventually caused the life of Jews to reflect the type of restrictions more common in Franco-German regions, Sephardim were certainly more influenced by Islam than by Christianity.
Jews under Islamic rule in Spain underwent varying degrees of Arabization or even Islamization which to a large extent reveals the ability of non-Muslims to integrate to a large measure in Islamic society.
The Ashkenazim as the only notable minority in Christian lands experienced a very different environment. While the idea of peaceful interaction is perhaps exaggerated with the regards to the idyllic picture of Jewish life in Spain, the complex relationships of Muslims and Christians and Jews provided the latter with a much more open society. The differences between the Sephardim and Ashkenazim were often as attributable to simple issues like economic reality to explain why variations in practice existed as they were to differences in religious philosophy and application. Because the differences are too many to fully describe, we will review the overall issues.
The differences between Ashkenazim and Sephardim of the medieval period extend to a various other areas including their liturgical practices, approaches to the Biblical and Talmudic study, manner of dress, food preferences, and of course differences in Hebrew pronunciation and writing. The differences often resulted in identity changes which manifested themselves in conflict and animosity towards each other. These conflicts remain alive to many in and outside the Land of Israel.
The differences were in largely reflective of very different cultural surroundings and the impact of the dominant political and religious cultures of Christianity and Islam. They were however also based on the older influences such as the differences between "Palestinian" and "Babylonian" practice, though neither group was completely reflective of either tradition. The influence of and movement between rabbis of note and rabbinic literature ultimately impacted both societies over time and the cross pollination between both communities is quite extensive.