AMMANNATI PICCOLOMINI, Jacopo. - Cardinal, b. 1422, d. 1479. He studied literature in Florence and earned a doctorate in jurisprudence at Siena. He served as secretary to Cardinal Domenico Capranica (1450–60) and, on account of his learning and piety, won the esteem of Callistus III, who appointed him Secretary of Briefs. His successor, Pius II, named him Bishop of Pavia (18 July 1460) and a year later created him Cardinal of S. Crisogono (18 Dec. 1461). In gratitude, Ammannati assumed the surname Piccolomini.
Paul II kept him at a distance, as he did the other cardinals of Pius II. Sixtus IV entrusted him with the legation of Umbria (Sept. 1471), which he soon resigned (July 1472). In August 1477 he was transferred to the see of Frascati and later to Lucca, though he retained administration of the diocese of Pavia. His final years were mostly spent outside Rome, in the Sienese territory. Siena granted him its citizenship.
He left various writings. Some have been lost, among them a collection of Lives of the Popes of his time, much to be regretted. Published in full are his Letters (782, from 1462 to 1479; ed. G. Gherardi, Milan 1506, and better, Frankfurt 1614) and the Commentaries, in seven books, which continue those of Pius II. Other letters survive in manuscript in the Vatican Archives (Arm. XXXIX, vol. X). Only part of a Diary of Consistories has appeared (ed. E. Carusi, in the new edition of the Rerum Italicarum Scriptores, XXIII, III, Bologna 1904).