Between them they rendered into Hebrew all the chief Jewish writings of the middle ages.
The precepts of the law were valuable in the eyes of the Scribes because they were the seal of Jewish particularism, the barrier erected between the world at large and the exclusive community of Yahweh's grace.
He was a considerable force in the educational revival of Jewish education in France.
In 1869 and 1871 he was president of the first and second Jewish Synods at Leipzig and Augsburg.
The crusaders brought back fresh developments; Gog and Magog (partly Arab and partly Greek) and some Jewish stories were then added.