Their escape from persecutions was always organized, which strengthened relations of community members and later turned into a duty of mutual aid and assistance, typical for members of Jewish Diaspora today. These times of horror and deprivations molded spirit and will of Jews, influenced the growth of cooperation of different communities all over Europe and resulted in moving to Eastern Europe, where they peacefully coexisted with local population up until 17th century. Unlike other nations it was already typical in the Middle Ages for Ashkenazi Jews to receive universal education, which was not only limited to Talmud and Torah studying. Sinful activities of money loaning, which were shameful for Catholics, were mostly occupied by Jews who achieved considerable success in finances all over Europe and gave them reputation of successful financiers and bankers.
Sepharadi Jews suffered persecution after the end of Reconquista in Iberian Peninsula. The main goal of queen Isabella was to convert Moor and Jewish population of former Cordoba caliphate into Christianity, so Jews had two options: either to leave the country or to adopt Catholicism. A small portion of Sepharadic Jews adopted Catholicism, secretly observing Judaism for the next several centuries. But in majority Sepharadi Jews left to Spanish colonies of South America, Southern Europe, Turkey and Holland...
Nevertheless, even those who adopted Christianity saved cultural particularities and language, enriching Spain culture, art and literature by original Jewish elements,.
Making a conclusion it's important to note that Jews are nearly the only nation, which was able to preserve its self-identity and culture under centuries of persecutions. They have adapted to the world they lived in and nearly always succeeded because of the strength of their communities, belief in God and education.
References
Jewish Life in Medieval Europe, available at http://www.aitzhayim.org/library_files/Katz%20on%20Jewish%20Life%20in%20Medieval%20Europe.htm
Zion Zohar A Global Perspective on Sephardic and Mizrahi Jewry, pp.1-20 available at http://www.nyupress.org/webchapters/0814797059chapt1.pdf
Bernard Lewis, The Jews of Islam Princeton, NJ: Princeton University Press, 1984
Jane Gerber, The Jews of Spain: A History of the Sephardic Experience (New York: Free Press, 1992), 89.
Haim Hillel Ben-Sasson, The History of the Jewish People Cambridge: Harvard University Press, 1976
Yitzhak Baer, A History of the Jews in Christian Spain, vol. 1 (Philadelphia: Jewish Publication Society, 1961), 319
Jewish Life in Medieval Europe
Jewish culture of medieval Europe
