The Spanish Conquest of 1521 brought about the fusion of Catholic attitudes and indigenous beliefs. The Day of the Dead was revealed as a result of amalgamation of Pre-Spanish Indian ritual beliefs and the imposed ritual and dogma of the Catholic church.
The 'Day of the Dead' is celebrated by many catholic countries, worldwide. This celebration originated with the Roman Catholic's, and was established in the Catholic calendar as an official holy day. The Catholic religion is based on works, and the theological idea of Purgatory has been accepted as a means of paying for sins, and buying your way into Heaven.
Those believers who died in a 'state of grace' were promised 'heavenly rewards', after paying for their sins in purgatorial flames, while those who did not die in a 'state of grace', were to spend eternity suffering in Hell. Catholics did, however, believe that they could pray their loved ones out of Purgatory. This practice gives us an idea of the spiritual significance of honoring the deceased.
November 1, is the official All Saints Day, which honors all saints who attained Beatific Vision, followed on November 2, All Soul's Day honoring the faithful departed. Generally, people celebrating this holiday will attend mass, sometimes exhibiting the relics of saints on a catafalque, and assist the souls of their loved ones from Purgatory to Heaven. They will then proceed to the cemetery to visit, bless and decorate the graves. This tradition is universal among Catholic countries, and accepted by the church.