PIUS III. (Francesco Todeschini), pope from September 22 to October 18, 1503, was born at Siena, May 9, 1439. As the nephew of Pius II. by his sister Laodamia, he was received into favour by that pontiff, who permitted him to assume the name and arms of the Piccolomini, and raised him, when only twenty-two years of age, to the see of Siena and the cardinalate. He was employed by subse-quent popes in several important legations, as by Paul II. at the diet of Ratisbon, and by Sixtus IV. to secure the restoration of ecclesiastical authority in Cmbria. Amid the disturbances consequent upon the death of Alexander VI. he was, by the not wholly disinterested influence of Cardinal Rovera, elected pope on September 22, 1503, his installation taking place on the 8th October following. He at once took in hand the reform of the papal court and arrested Caesar Borgia; but after a brief pontificate of twenty-six days he died (October 18, 1503) of an ulcer in the leg, or, as some have alleged, of poison administered at the instigation of Pandolfo Petrucci, governor of Siena. He was succeeded by Julius II.