Pope Pius XI instituted a new rule for setting the date for the start of a papal conclave to elect a new pope by promulgating the document Cum proxime on 1 March 1922, less than a month after his own election. The four non-European cardinals had not participated in the conclave that elected him in February. Three of them arrived too late and one did not attempt the journey. With Cum proxime, Pius XI extended the time between the death of a pope and the start of the conclave to increase the likelihood that cardinals from distant locations could reach Rome in time to participate.