After Jesus, the two most significant figures in Christianity are the apostles Peter and Paul/Saul. Paul, in particular, takes a leading role in spreading the teachings of Jesus to Gentiles (non Jews) in the Roman Empire.
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.