Lutheranism is a branch of Christianity that originated in the 16th century, founded by Martin Luther, a German monk. It emerged as a response to certain practices of the Roman Catholic Church, particularly the sale of indulgences. Luther's teachings emphasized salvation through faith alone, the authority of the Bible, and the priesthood of all believers, which challenged traditional church hierarchies. Lutheranism is characterized by its focus on grace and the importance of scripture. It has various denominations, with the Evangelical Lutheran Church in America being one of the largest in the United States. Worship services often include hymns, prayers, and a strong emphasis on preaching.