What is the origin of All Saints Day?

Answer 1

All Saints' Day, feast of the Roman Catholic and Anglican churches, and day on which churches glorify God for all God's saints, known and unknown. It is celebrated on Nov. 1 in the West, since Pope Gregory IV ordered its church-wide observance in 837. Its origin lies earlier in the common commemorations of martyrs who died in groups or whose names were unknown, which were held on various days in different parts of the Church; over time these celebrations came to include not only the martyrs but all saints. During the Reformation the Protestant churches understood "saints" in its New Testament usage as including all believers and reinterpreted the feast of All Saints as a celebration of the unity of the entire Church. In medieval England the festival was known as All Hallows, hence the name Halloween [=All Hallows' eve] for the preceding evening.

Roman Catholic Answer

from The Order of Prayer in the Liturgy of the Hours and Celebration of the Eucharist 2010, compiled by Rev. Peter D. Rocca, C.S.C., Paulist Press Ordo, Mahwah, NJ © 2009

All Saints First mentioned in the 4th century Eastern feast of All Martyrs (13 May) and attested to by St. Ephrem of Edessa (†373), this feast came to be celebrated on other days as well in the East, e.g., Easter Friday, and the Sunday after Pentecost, the day of its observance in some places in the West. In 609 or 610, the Roman Pantheon was dedicated on 13 May under the title S. Maria ad Martyres. Many see in this the origin of All Saints Day. For reasons which are unclear, Pope Gregory IV (827-844) transferred the feast from May to 1 November, adopting perhaps the English-Gallican practice dating from the first quarter of the 8th century.

from A Catholic Dictionary, edited by Donald Attwater, Second edition, revised 1957

The feast (Nov. 1 in the Western Church) on which are commemorated all the saints of God, canonized and uncanonized, known and unknown. It is a feast of the highest rank, with a fasting vigil and an Octave. It was formerly often called All Hallow's in England. Religious orders have a feast of all the saints of their order later in the month. In the Byzantine rite it is kept on the first Sunday after Pentecost and on other days in other rites. "The feast of All Saints seems to me to be in some sort a greater than that of Easter or the Ascension. Our Lord is perfected in this mystery, because, as our Head, he is only perfect and fulfilled when he is united to all his members, the saints . . . it is glorious because it manifests exteriorly the hidden life of Jesus Christ. The greatness of perfection of the saints is entirely the work of his spirit dwelling in them" (M. Olier)

Answer 2

The Feast of All Souls Day has a long history. To learn more about it I have placed a link below. A Saints and All Souls are interwoven in their history.

Roman Catholic Answerfrom Encyclopedia of Catholic Devotions and Practices by Ann Ball, Our Sunday Visitor, Inc. C 2003

The annual commemoration of all the faithful departed, November 2.

The dead were prayed for from the earliest days of the Church. By the sixth century, Benedictine monasteries customarily held commemorations for departed members at Pentecost. A common commemoration of all the faithful departed on the day after All Saints' Day was begun in the Abbey of Cluny by St. Odilio in 998. Five years later, it was recommended and approved by Pope Sylvester II, and from the eleventh to the fourteenth centuries the feast gradually spread throughout Europe.

In the Western Church, All Souls Day was set for November 2 so that the memories of all the souls, both of the saints in heaven and the souls of those in purgatory, could be celebrated on two successive days. In this way, the Christian belief in the communion of saints could be more clearly expressed. In Eastern Rites, commemorations for the souls in purgatory are celebrated during the Easter season.

Throughout the world, numerous customs and pious traditions were associated with the celebrations in honor of the dead. Almost all ethnic traditions include special prayers, decorations, foods, lights, and the visiting and maintenance of graves. Some groups distribute food to the poor on this day, and others visit graves of the "forgotten," plots that would otherwise remain neglected and unadorned.