Protestants are a branch of Christianity that originated in the 16th century during the Reformation, a movement aimed at reforming the practices of the Roman Catholic Church. Key figures like Martin Luther and John Calvin challenged certain church teachings, leading to the formation of various Protestant denominations. They emphasized the importance of the Bible and individual faith over church traditions. Today, Protestantism includes many different groups, such as Baptists, Methodists, and Lutherans. Each denomination has its own beliefs and practices, but they generally share core principles like salvation through faith in Jesus Christ and the authority of Scripture.