The first, and most prominent, was the popularization of the mystical lore of Kabbalah. For several centuries, an esoteric teaching practiced surreptitiously by few, it was transformed into almost household knowledge by a mass of cheap printed pamphlets. The kabbalistic inundation was a major influence behind the rise of the heretical Sabbatean movement, led by Sabbatai Zevi, who declared himself Messiah in 1665. The propagation of Kabbalah made the Jewish masses susceptible to Hasidic ideas, themselves, in essence, a popularized version of the teaching – indeed, Hasidism actually emerged when its founders determined to openly practice it, instead of remaining a secret circle of ascetics, as was the manner of almost all past kabbalists. The correlation between publicizing the lore and Sabbateanism did not escape the rabbinic elite, and caused vehement opposition to the new movement.