All Souls Day is a day of prayer and remembrance for the faithful departed, observed by certain Christian denominations on November 2. It is a day for commemorating all the faithful departed, those baptized Christians who are believed to be in purgatory because they died with the guilt of lesser sins on their souls. The day is dedicated to prayer and remembrance, and requiem masses are commonly held. The prayers of the faithful on earth are believed to help cleanse these souls in order to fit them for the vision of God in heaven.

The institution of a day for a general intercession on November 2 is due to Odilo, abbot of Cluny (died 1048). The date, which became practically universal before the end of the 13th century, was chosen to follow All Saints’ Day. Having celebrated the feast of all the members of the church who are believed to be in heaven, the church on earth turns, on the next day, to commemorate those souls believed to be suffering in purgatory.

All Souls Day is primarily celebrated in the Catholic Church, but it is also celebrated in the Eastern Orthodox Church and a few other Christian denominations. In Western Christianity, including Roman Catholicism and certain parts of Lutheranism and Anglicanism, All Souls Day is the third day of Allhallowtide, after All Saints Day (November 1) and All Hallows Eve (October 31).

People commemorate the poor souls in purgatory and gain them indulgences through prayer, intercessions, alms, and visits to cemeteries. It is a day for being with family, visiting cemeteries, sharing memories of loved ones, and honoring traditions. Although it is not a Holy Day of Obligation, it is a good idea to attend Mass on All Souls Day.