What does the “Pontifical Honour of Protonotary Apostolic” mean, and what does the “Prelate of Honour” mean?
Priests who are bestowed with one of these two titles by Pope John Paul II are now monsignors. They have been recognized as “outstanding members of the local clergy”. The current system of bestowing papal honours on clergy was set out by Pope Paul VI, in the document Pontificalis Domus. Most monsignors have the title Prelate of Honour. Protonotary Apostolic is the highest rank of monsignor. Protonotaries apostolic may wear purple vestments, and may use the initials P.A. after their names. Both prelates of honour and protonotaries apostolic are addressed as “Reverend Monsignor”. Source: “The Church Visible”, by James-Charles Noonan, Jr.