By its own reading of history, Roman Catholicism originated with the very beginnings of Christianity. An essential component of the definition of any one of the other branches of Christendom, moreover, is its relation to Roman Catholicism: How did Eastern Orthodoxy and Roman Catholicism come into schism?
Who is the leader of the Protestant Church?
Martin Luther, often called the father of Protestantism, fundamentally changed the Christian world through his force of will and new ideas. He tried passionately to reform the Catholic Church.