The Protestant tradition arose from discontent and disagreement with the Roman Catholic Church. The seminal figure in its history is Martin Luther, a Catholic priest who came to lead the Protestant Reformation of 1517. At that time, Luther posted 95 theses, or articles of debate, on a church door in Wittenberg, Germany. He questioned various Catholic practices and doctrines and strongly condemned abuses by the clergy. Through public appearances and especially through the new medium of print, Luther gathered support for his ideas.
As a result, growing numbers of people began to break away from the Roman Catholic Church, forming their own congregations and establishing their own doctrines and practices. Those who followed Martin Luther's interpretation of the Christian faith became known as Lutherans, but there were also many people who developed or followed other interpretations, giving rise over time to such Protestant denominations as Methodism and Presbyterianism.
Today, the six largest Protestant groups in the United States are the Assemblies of God, Baptists, Episcopalians, Lutherans, Presbyterians, and United Methodists. Many other Protestant congregations are not formally associated with any particular denomination and therefore may be called nondenominational churches. The leaders of all Protestant congregations are Protestant ministers.