Papal Nuncio And Legate
A nuncio is an official permanent papal representative from the Holy See to both the state and the church of a given area. Usually a titular bishop or archbishop, he relates to the Holy See through the Cardinal Secretary of State. As papal envoy to the state, he has duties diplomatic in character, not unlike an ambassador in international relations; his ambassadorial status was recognized by the Congress of Vienna (1815). As papal envoy to the area church, he has duties ecclesiastical, like those of an apostolic delegate in areas where there is no nuncio. “Legate” was the usual designation of a papal representative during the era of the seventeenth century and earlier. Three or four types are at times distinguishable: Legate nati, the principal resident bishop, who also held certain special authority from the pope, duties partially retained by a primate today; Legates missi, sent by the Pope on ad hoc missions; and Legate a latere, the highest rank of special papal envoy, today a title usually reserved for ceremonial functions. A fourth type, the nuncii et collectores, were financial officials charged with gathering papal funds. The modern nuncio gradually replaced and absorbed duties drawn from all such earlier legates as the structures of the papacy, the area churches, and the states became more distinct.
See R.A. Graham, Vatican Diplomacy, A Study of Church and State on the International Plane (1959), and I. Cardinale, Le Saint-Siège et la diplomatie; aperçu historique, juridique, et pratique de la diplomatie pontificale (1962).