The salutation should be Dear Father. To be even more polite, refer to a priest as His Reverence. If it’s a very formal letter, say, “The Reverend Father last name as the salutation or Dear Reverend Father.”
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.