All Hallows' Eve (or Halloween), All Saints' Day and All Souls' Day are collectively observed as "Los Dias de los Muertos" (The Days of the Dead), particularly in Mexico. It's a time marked by festivities, including spectacular parades of skeletons and ghouls, and revelers often lead a mock funeral procession with a live person inside a coffin.
For Roman Catholics, Anglicans, Lutherans and other Christians, Saturday, Nov. 1, is All Saints' Day. Eastern churches observe the holy day on the first Sunday after Pentecost. All Souls' Day (sometimes called the "Day of the Dead") is always Nov. 2 (Nov. 3rd if the 2nd falls on a Sunday).
Now a day to honor all saints, even those not known by name, All Saints' Day began as the Feast of All Holy Martyrs, which was proclaimed May 13, 610 A.D., by Pope Boniface when the Emperor Phocas presented him with the Pantheon in Rome. During Pope Gregory III's reign, the festival was expanded to include all saints, and in 835, Pope Gregory IV changed the date to Nov. 1.
For Roman Catholics, the Orthodox and to some extent Anglicans, All Saints' is a day to remember, thank God for and to venerate and pray to the saints in heaven for various helps. For Lutherans, the day is observed by remembering and thanking God for all saints, both dead and living. It is a day to glorify Jesus Christ, who by his holy life and death has made the saints holy through Baptism and faith.
In the early days, Christians were accustomed to solemnizing the anniversary of a martyr's death for Christ at the place of martyrdom. In the persecution of Diocletian, the number of martyrs became so great that a separate day could not be assigned to each. The Church, feeling that every martyr should be venerated, appointed a common day for all.
At first, only martyrs and Saint John the Baptist were honored by a special day. Other saints were added gradually and increased in number when a regular process of canonization was established.
All Souls' Day, a Roman Catholic day of remembrance for friends and loved ones who have passed away, has its roots in the ancient Pagan Festival of the Dead.
Purposely following All Saints' Day to shift the focus from those in heaven and the glory there to those in purgatory, All Souls' Day is celebrated with Masses in honor of friends and loved ones who have died and reminders of our obligations to live holy lives. The living pray for the removal of sin from the souls of dead Christians so that they will be received into heaven. At present, some Christians believe the souls are in purgatory, the state in the afterlife where souls must suffer to be purified.
Through prayer and good works, living members of the church may help their departed friends and family. There are three Requiem Masses said by the clergy to assist the souls from purgatory to heaven: one for the celebrant, one for the departed and one for the pope.
The Feast of All Souls began with seventh-century monks who decided to offer the Mass on the day after Pentecost for their deceased community members. The Benedictine monastery moved the Mass to Nov. 2, the day after the Feast of all Saints.
To celebrate All Souls' Day, an offering of food is placed on an altar so that the dead can partake in spirit, and the living eat it later. The ofrendas (offerings) are beautifully arranged with flowers such as marigolds (zempasuchitl), the traditional flower of the dead. A decorated candle is placed for each dead soul, and incense is also often used. Photos and other remembrances of the dead also adorn the ofrenda.
Another tradition in some places is performance of the play "Don Juan Tenorio." Masks, papier mâché and sugar skulls are popular, as are cardboard coffins from which a skeleton can jump out.
Traditional Catholics still honor customs related to the relief of the souls suffering in purgatory. One custom is for individuals to pray six Our Fathers, Hail Marys and Glory Bes for the intentions of the Pope in a church and, thereby, receive a plenary indulgence for a soul in purgatory. This action may be repeated for another soul by leaving the church and re-entering it to repeat the prayers.