Methodism, also called the Methodist movement, is a group of historically related denominations of Protestant Christianity which derive their doctrine of practice and belief from the life and teachings of John Wesley. George Whitefield and John's brother Charles Wesley were also significant early leaders in the movement. They were named Methodists for "the methodical way in which they carried out their Christian faith". Methodism originated as a revival movement within the 18th-century Church of England and became a separate denomination after Wesley's death. The movement spread throughout the British Empire, the United States, and beyond because of vigorous missionary work, today claiming approximately 80 million adherents worldwide.