The Protestant Reformation began in 1517 with Martin Luther publishing his 95 Theses challenging Catholic Church practices. Over the next century, reformers like Luther, Calvin, and Henry VIII promoted ideas like sola scriptura and challenged papal authority, leading northern Europe like Germany and Switzerland to adopt Protestantism as the dominant religion. The Catholic Church responded with the Counter-Reformation, reforming itself through the Council of Trent while also persecuting Protestants. Today, the Reformation continues to impact principles of religious freedom, separation of church and state, and widespread access to scripture in local languages.