A Christian religious holiday observed primarily by the Catholic Church, All Souls’ Day follows All Saints’ Day, or November 2 and November 1, respectively. All Souls’ Day is also known as the Feast of All Souls, and Commemoration of all the Faithful Departed. In Spanish-speaking countries, its name is the Day of the Dead (Dia de los Muertos).
The theological basis for the holiday is the doctrine that at least some of the souls of the faithful may not be fully purged of sin when they die, so they wait in Purgatory to achieve full sanctification and thereby entry to heaven. This process can be assisted by prayers from the living, so the latter are called to participate in Morning and Evening Prayer (Lauds and Vespers) on this day.
This 1859 painting, "The Day of the Dead," is by the French academic painter William-Adolphe Bouguereau (1825-1905).