These studies explore the history of the Jewish minority of Ashkenaz (northern France and the German Empire) during the High Middle Ages. Although the Jews in medieval Europe are usually thought to have been isolated from the Christian majority, they actually were part of a ‘Jewish-Christian symbiosis.’ A number of studies in the collection focus on Jewish-Christian cultural and social interactions, the foundations of the community ascribed to Charlemagne, and especially on the fashioning of a martyrological collective identity in 1096. Even when Jews resisted Christian pressures they often did so by internalizing Christian motifs and turning them on their heads to argue for the truth of Judaism alone. This may be seen especially in the formation of Jews as martyrs, a trope that places Jews as collective Christ figures whose suffering brings about vicarious atonement. The remainder of the studies delve into the lives and writings of a group of Jewish ascetic pietists, Hasidei Ashkenaz, which shaped the religious culture of most European Jews before modernity. In Sefer Hasidim (Book of the Pietists), attributed to Rabbi Judah the Pietist of Regensburg (d. 1217), one finds a mirror of everyday Jewish-Christian interactions even while the author advances a radical view of Jewish religious pietism.