An official mourning period of nine days, called the Novendiales, begins when a Pope dies. The day of death is counted as the first day of this period. On each of these nine days the Mass of each Cardinal must be a funeral rite for the Pope.

Indeed, the Missal provides a Mass formula "For a Deceased Pope" which can be used by any priest during this time, if the liturgical season permits.

Prior to his burial, and following private rites in the Sistine Chapel, the Pope is laid in state in St. Peter’s Basilica, permitting the faithful to pay their respects. Between the fourth and sixth day after his death (that is, on the 5th, 6th or 7th day of the mourning period) a Solemn Funeral is celebrated in St. Peter’s Basilica by the Dean of the College of Cardinals, with the other Cardinals. The deceased Pope is then buried, most likely in the crypt of St. Peter’s. The mourning period then continues until the nine days are completed.