The Papal conclave of 1958 occurred following the death of Pope Pius XII on October 9, 1958 in Castel Gandolfo, after a 19-year pontificate. The conclave to elect his successor commenced on October 25 and ended three days later, on October 28, after eleven ballots. The cardinal electors chose Angelo Roncalli, then Patriarch of Venice, as the new pope. He accepted the election and took the regnal name of John XXIII.