We've got three big dates for September 17:
In 1179, Hildegard von Bingen died. The renowned German composer and prophetess wrote about the lurid visions she experienced - including the Whore of Babylon birthing a black-headed child within a cathedral nave. She took this to mean that the coming Antichrist would be brought forth from within the institutions of the Catholic Church. Despite this sort of thing, Hildegard was canonized a Saint by Pope Benedict XVI just this past May.
In 1575, Heinrich Bullinger died. In his "One Hundred Sermons upon the Apocalypse of Jesu Christ", he preached from Zurich that the fin du siecle, or end of the world, would occur in 1557.
And in 1676, Shabbati Zevi died. A Kabbalist from Montenegro, he claimed to be the Messiah, and led 300 families of followers as far east as Istanbul en route to reclaim the Holy Land for Israel. In Turkey, however, the Ottoman Sultan arrested Zevi, who converted to Islam under threat of death.
