5. Varieties of Non-Rabbinic Judaism in Geonic and Contemporaneous Sources

In ‘Varieties of Non-Rabbinic Judaism in Geonic and Contemporaneous Sources’, Robert Brody shows that, based on his analysis of several responsa attributed to Natronai Gaon and the letter of Pirqoy ben Baboy, rabbinic authorities were aware of the existence of several non-rabbinic Jewish groups in the eighth century. However, over the course of a little more than a century, rabbinic discourse shifted from knowledge of several such groups to the assumption that all non-rabbinic teachings derived from Anan ben David and his followers. Finally, Brody pinpoints several differences between the earlier non-rabbinic groups (on the one hand) and the Ananites and Karaites (on the other), who seem to have posed a greater threat to the rabbis.