Complex sentence: Granville Sharp, Thomas Clarkson, and William Wilberforce--all evangelical Christians sympathetic to the religious revival that had predominantly Nonconformist origins, but which sought wider non-denominational support for a "Great Awakening" amongst believers.
Split into simpler sentences: Granville Sharp, Thomas Clarkson, and William Wilberforce--all evangelical Christians. They were sympathetic to the religious revival that had predominantly Nonconformist origins, but which sought wider non-denominational support for a "Great Awakening" amongst believers.