Complex sentence: Endecott was a zealous and sometimes hotheaded Puritan, but was also sympathetic to Separatist attitudes toward the Anglican Church, which sometimes put him at odds with Nonconformist views that were dominant among the colony's early leaders, especially when he gave shelter to Roger Williams.
Split into simpler sentences: Endecott was a zealous and sometimes hotheaded Puritan, but was also sympathetic to Separatist attitudes toward the Anglican Church. This sometimes put him at odds with Nonconformist views that were dominant among the colony's early leaders, especially when he gave shelter to Roger Williams.