In the year 1665 to1666 there arose a figure in the Jewish world who had an impact that was felt across much of the known world. He claimed to be the Messiah, the anointed one who would rescue the Jewish people from exile . In 1666 he announced that he would subjugate the Ottoman Sultan. The opposite occurred. Shabbtai Tzvi converted to Islam.
This about killed the movement it some people still held on. Who were most of these Jews who followed him and why did they follow him? Many of the people who followed him were conversos or anusim. These Jews were forced to adopt Catholicism or were born into it. They know what it was like to be forced into another religion .
Within the Jewish world there were major changes brewing. One of them was a heightened interest in Kaballah . Lurianic Kaballah opened the idea of messianism and put more of an emphasis on the mystical. It created a cadre of new elites within the Jewish world.
There was also less emphasis on the mitzvah and studying the law or Halacha. These changes in the Jewish world plus the many persecutions they experienced opened the way for someone like Shabbtai Tzvi to rise up.