 According to Moses Cordovero, halakhically, one must be of age twenty to engage in the Kabbalah.Many famous kabbalists, including the ARI, Rabbi Nachman of Breslov, Yehuda Ashlag, were younger than twenty when they began.The Sabbatian movement was followed by that of the Frankists, disciples of Jacob Frank (1726–1791), who eventually became an apostate to Judaism by apparently converting to Catholicism.