It was St. Odilo, the abbot of Cluny in France, who in the 10th century proposed that the day after All Saints’ Day be set aside in honor of the departed—particularly those whose souls were in purgatory. Today, the souls of all the faithful departed are commemorated. In many Catholic countries, people attend churches and visit family graves on this day to honor their ancestors. In Mexico, it is a national holiday called Día de los Muertos (or Day of the Dead). Orthodox Christians commemorate the dead on the second Saturday before Lent begins and on the day before Pentecost. Discuss
Source: The Free Dictionary