Also also worn by many Protestant Ministers
1536 Holy Orders is the sacrament through which the mission entrusted by Christ to his apostles continues to be exercised in the Church until the end of time: thus it is the sacrament of apostolic ministry. It includes three degrees: episcopate, presbyterate, and diaconate.
more to come on this .....
nuns, monks, priests, monsignors, bishops, cardinals, pope
Assistant to pope
He is a higher class priest and called Camerlengo.