The papal conclave, October 1503 elected Giuliano della Rovere as Pope Julius II to succeed Pope Pius III. The conclave took place during the Italian Wars barely a month after the papal conclave, September 1503, and none of the electors had travelled far enough from Rome to miss the conclave. The number of participating cardinals was thirty-eight, the College of Cardinals having been reduced by the election of Piccolomini as Pius III, who did not elevate cardinals.
Mostly because of the lack of a conclave capitulation, the conclave took only ten hours, the shortest in history.
The previous conclave in September had been marked by the Italian Wars, surrounded by the forces of Louis XII of France, Ferdinand II of Aragon, and Cesare Borgia, the former cardinal-nephew of Pope Alexander VI. Georges d'Amboise had been the favorite of Charles VIII, Piccolomini (who was the favorite of the bookmakers gambling on papal elections) had been elected, and the candidacy of della Rovere was also a strong papabile.
Pius III had died after just 26 days in office. This was insufficient time for the Cardinals to disperse very far, so they were all able to return for the new conclave.
The cardinal electors were the same as those that had convened in September, minus Piccolomini who had previously been elected, and then died.
In the month between the conclaves, della Rovere met with Cesare Borgia and the Spanish cardinals, whose support he lacked in the previous conclave, and assured them he would maintain Cesare's command of the papal army and territorial possessions in Italy. Cesare delivered the support of all eleven Spanish cardinals.
Ascanio Sforza and his faction were standoffish at first, but vote for della Rovere on the first scrutiny due to various promises of favors. The vote was "unanimous" for della Rovere on the first ballot, with the exception of his own vote. Louis XII of France who had opposed Piccolomini a month earlier—exclaiming about Cesare "that son of a whore has prevented Rouen from becoming pope!"— accepted the election of della Rovere, although they would soon be at war once Julius II formed the Catholic League.
- Baumgartner, Frederic J. 2003. Behind Locked Doors: A History of the Papal Elections. Palgrave Macmillan. ISBN 0-312-29463-8.