Passionei, Dominic a learned Italian cardinal, was born of an ancient noble family at Fossoinbrone, in the duchy of Urbino, Dec. 2, 1682, and was educated in the Clementine College at Rome under the direction of Tomasi and Fontanini. In 1706 he went with Gualterio, the nuncio. to Paris, and, having passed two years in the French capital with the legate, he was sent in 1708 to La Haye as diplomatic agent of the pope. He was appointed in 1712 to the Congress of Utrecht, and in 1714 to that of Baden. He formed ties of friendship with prince Eugene. On his return to Rome in 1715 he resumed his studies upon classical and ecclesiastical antiquity, and entered into an active correspondence with the principal learned men of Europe. Pope Innocent XIII made him titular archbishop of Ephesus. He was also the same year appointed nuicio to the Catholic cantons of Switzerland, and interposed in the debate which arose in 1725 between the bishop of Constance and the government of Lucerne regarding the deposition of a curd who had forbidden his parishioners to dance. Things went so far that Passionei removed his residence from Lucerne to Altorf, and a monitory letter, which must precede suspension, was issued against the council of Lucerne. Finally, by the interposition of the cardinal du Fleury, the affair was settled in 1727 by a favorable consideration of the claims of the Lucerne government, Passionei took exception to the arrangement, and did not return to Lucerne. In 1730 he was appointed nuncio to the imperial court; recalled to Rome in 1738, he was created cardinal by pope Clement XII. In 1755 pope Benedict XIV appointed Passionei librarian of the Vatican, in which situation he promoted Dr. Kennicott's great undertaking by causing the Hebrew manuscripts to be collated for his use, and the Academy of Inscriptions and Belles Lettres chase him in the same year one of its foreign associates. At the conclave of 1758 he obtained eighteen votes; and but for his antipathy to the Jesuits, on which subject several extravagant anecdotes are related. he might have been elected pope. He warmly opposed the canonization of cardinal Bellarmine, and is said to have proscribed from his library all works written by Jesuits. He died near Rome July 5, 1761. His death was attributed to chagrin at signing the brief of condemnation issued against the "Exposition of Christian Doctrine" by the Jansenist Mesengui (q.v.). Passionei had gathered in his villa at Frascati a rich collection of inscriptions and objects of antiquity. His books were published after his death by the Augustine monastery, and added to their fine library, which is styled the Angelica, and is one of the principal public libraries at Rome. His nephew, Benedict Passionei, published a volume containing all the Latin and Greek inscriptions collected by the cardinal (Lucca, 1765; fol.). We have of his works, Acta apostolicae legationis Helveticae (Zug, 1724; Rome, 1738, 4to); — in which nothing is found concerning the contest of Passionei with the council of Lucerne: — Oratio fumebris in Principem Eugenium (Vienna, 1737; in Italian, Padua, 1737): — Letters in different collections such as the Tempe Helvetica (vol. 4), in the Commercium Epstolicum of Uffenbach, etc. See Goujet, Eloge du Cardinaul Passionei (La Haye, 1763, 12mo); Galetti, emorie peer la Vita del Cardinal Passionei (Rome, 1762, 4to); Le Beau, Eloge du Cardinal Passionei (in vol. 31 of L'Histoire de l'Academie des Inscriptions); Moreri, Dict. Hist. s.v.