Rabbi Moses ben Maimon, better known as Maimonides or "The Rambam" (1135–1204 CE), lived at a time when both Christianity and Islam were developing active theologies. Jewish scholars were often asked to attest to their faith by their counterparts in other religions. The Rambam's 13 principles of faith were formulated in his commentary on the Mishnah (tractate Sanhedrin, chapter 10). They were one of several efforts by Jewish theologians in the Middle Ages to create such a list. By the time of Maimonides, centers of Jewish learning and law were dispersed geographically. Judaism no longer had a central authority that might bestow official approval on his principles of faith.