September 1503 Conclave
elected Pius III16–22 September 1503 · The early modern conclaves · Apostolic Palace, Papal States
The September 1503 conclave elected Pope Pius III to succeed Pope Alexander VI. Due to the Italian Wars, the College of Cardinals was surrounded by three potentially hostile armies, loyal to Louis XII of France, Ferdinand II of Aragon, and Cesare Borgia (the cardinal-nephew and illegitimate son of Alexander VI).
Elected pope
Pius III
Francesco Piccolomini
Succeeded
Alexander VI
Duration
7 days
2 ballots
Cardinal electors
39
locked in under conclave rules
Key officials
| Dean | Giuliano della Rovere |
| Camerlengo | Raffaele Riario |
Ballot-by-ballot tallies are destroyed by design — the paper is burned in the stove whose smoke announces the result — so this entry records what the Church documents: the dates, the electors, the number of ballots where known, and the man who walked out onto the balcony.