|Dates||August 31–September 3, 1914|
|Location||Sistine Chapel, Apostolic Palace, Vatican City|
|Vice Dean||Francesco di Paola Cassetta|
|Camerlengo||Francesco Salesio Della Volpe|
|Protodeacon||Francesco Salesio Della Volpe|
|Ballots||Pope elected after 10 ballots|
|Elected Pope|| Giacomo della Chiesa |
(took name Benedict XV)
With Europe facing World War I, whoever was selected would face the difficulty of leading the Holy See through the war to end all wars, in which Catholic Belgium and France were attacked by Protestant Germany, which was supported by Catholic Austria while the Protestant United Kingdom of Great Britain and Ireland (including Catholic Ireland) and Russian Orthodox Russia sided with France. Critics wondered whether the Holy See should remain neutral or whether it should assume a position of moral leadership by casting public judgments on the behaviour of the various combatants.
The conclave brought together cardinals from the combatant nations, including Károly Hörnig from Austria-Hungary, Louis Luçon from France, Felix von Hartmann from Germany and two from the United Kingdom of Great Britain and Ireland, Francis Bourne (from England & Wales) and Michael Logue (from Ireland).
After the lying-in-state and funeral of the popular but controversial Pope Pius X, cardinals assembled for the conclave at the end of August 1914. One major difference with earlier conclaves was that this time no secular monarch claimed a veto over whomever the cardinals could select as pope, as a result of legislation promulgated by Pius X, that established that whosoever attempted to introduce a veto in the conclave would incur automatic excommunication. For the first time in centuries the cardinals alone would make the choice.
The conclave itself assembled in the Sistine Chapel on 31 August. From the beginning of the conclave, it was clear that there were only three possible winners. Domenico Serafini, a Benedictine and assessor at the Holy Office won the support of the Curia to continue Pius X's anti-modernist campaign as his chief priority. However, many other cardinals, such as Carlo Ferrari and Desiré Merciér, believed that a Pope with a different focus was needed and supported the Archbishop of Pisa Pietro Maffi, considered very liberal but tainted by being close to the House of Savoy. Giacomo della Chiesa, Archbishop of Bologna, stood intermediate between Maffi and Serafini, but in the early ballots he was equal with Maffi and seemed to be winning some support from conservative factions. Della Chiesa drew ahead by five votes after the fourth ballot, and once it became clear Maffi had no hope whatsoever of gaining two-thirds of the votes, Serafini became Della Chiesa's opponent. By 3 September 1914, on the tenth ballot, all of Maffi's supporters had switched to him and Della Chiesa had been elected pope. He took the name Pope Benedict XV.
Reportedly Della Chiesa had been elected by one vote. According to the rules in force at the time, the ballot papers had a numbering on the reverse side, so that, if the election was decided by only one vote, it could be checked whether or not the elected person had voted for himself, in which case the election would be void. According to that account, Cardinal Rafael Merry del Val, who had been Pius X's Secretary of State, insisted that the ballots be checked to ensure that Della Chiesa had not voted for himself - he had not. When the cardinals offered their homage to the new pope, Benedict allegedly said to Merry del Val, "The stone that the builders rejected has become the cornerstone." To which the unabashed Merry del Val replied with the next verse of Psalm 118: "This is the Lord’s doing; it is marvelous in our eyes." 
Cardinal Merry del Val wasn't reappointed as Secretary of State by the new Pope, but was named Secretary of the Supreme Sacred Congregation of the Holy Office (then the head of that Dicastery, because the Popes themselves retained the office of Prefect of the Holy Office, leaving its daily administration to the secretary).
|LENGTH OF CONCLAVE||4 days|
|NUMBER OF BALLOTS||10|
|DECEASED POPE||PIUS X (1903-1914)|
|NEW POPE||BENEDICT XV (1914-1922)|