Complex sentence: Her strong religious convictions were at odds with the established Puritan clergy in the Boston area, and her popularity and charisma helped create a schism in the Boston church that threatened to destroy the Puritans' religious experiment in New England.
Split into simpler sentences: Her strong religious convictions were at odds with the established Puritan clergy in the Boston area. Her popularity and charisma created a schism in the Boston church which threatened to destroy the Puritans' religious experiment in New England.