According to the Catechism of the Catholic Church, Catholic ecclesiology professes the Catholic Church to be the “sole Church of Christ” – i.e., the one true church defined as “one, holy, catholic, and apostolic” in the Four Marks of the Church in the Nicene Creed.
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.