Legate (Lat. legatus, one sent with a charge), in ancient Rome, the title given to an ambassador, or to the lieutenant of the supreme civil and military magistrate; in ecclesiastical history, the title of the representative of the pope in the government of one of his temporal provinces, or in his intercourse with sovereigns or with national churches. The Roman senate alone appointed ambassadors, who were generally chosen from among persons of consular rank. Under the republic the dictator, consul, proconsul, and praetor chose their own legati or lieutenants, subject to the approval of the senate. Under the empire, the legati Coesaris were the lieutenants of the emperor in certain provinces the administration of which was reserved to himself. - The representatives of the bishop of Rome at imperial and royal courts, or in councils, or despatched for the settlement of some ecclesiastical difficulty, received the title of legati at a very early date. In the middle ages legates fell under a threefold distinction: legati d latere or de latere, persons delegated "from the side" of the pontiff, who were generally cardinals; legati missi or dati, or nuntii apostolici, "apostolic nuncios;" and legati nati, or "legates born," a title formerly attached to certain ecclesiastical dignities.

The archbishops of Canterbury, Toledo, Mentz, Lyons, and Aries claimed in media3val times the honorary title of "legates born" of the holy see. This title has now fallen into abeyance. That of legate d latere is bestowed on a cardinal sent by the pope on a special mission to a foreign court. This title was also formerly bestowed on the governors of the chief pontifical provinces, hence called legations, such as Ferrara; those not governed by cardinals being called delegations. At present the resident ambassadors or legates of the holy see near first-class powers are called nuncios, and those at second-rate courts have the title of internuncio. Legates d latere in mediaeval times claimed in all cases, in the countries to which they were sent, the same power as the pope himself when present. This was limited by the council of Trent; and in modern custom legates claim power only for the special cases for which they are sent, and do not interfere with the ordinary jurisdiction of bishops.