ANNIBALE. - Cardinal, b. at Urbino in 1682, d. at Rome in 1751. Brother of Alessandro and nephew of Clemente XI, after having been a canon of S. Pietro and president of the Apostolic Camera, he was sent in 1709 as extraordinary nuncio for the peace between the Austrian Empire and the German States, remaining for two years in Vienna. The result of his mission was the ratification of the election of Carlo VI as emperor. He then went to the Elector of Saxony, King of Poland, to regulate the situation of the Catholics and, having been created cardinal in 1711, was first secretary of Memorials, then camerlengo of the S. Romana Chiesa and archpriest of the Vatican Basilica. Bishop of Sabina in 1730, he held the synod which he published in 1737 and which was highly praised by Benedetto XIV.
Sub-dean of the S. Collegio and bishop of Porto e S. Rufina in 1743, as soon as the reform of the Roman Archiginnasio by Benedetto XIV was announced (1747), he resigned from the office of camerlengo and archchancellor of the Sapienza. During his cardinalate he worked assiduously and tenaciously to have Augusto II recognized by the S. Sede as King of Poland, for which he came into disagreement with Luigi XIV.
He published in several volumes, dedicated to the S. Collegio, the works of his uncle, bulls, briefs, and the Pontificale Romanum Clementis XI auctoritate recognitum (1720).