“The present form of the celebration of Day of the Dead in Mexico has come about through a lengthy and circuitous historical development, which has resulted in the fusion of certain southern European folk practices, medieval and Renaissance catholic rituals, and indigenous Mesoamerican customs.”
Kristin Norget Days of Death, Days of Life: Ritual in the Popular Culture of Oaxaca. Columbia University Press, New York. P. 193
There is often a link made to pre-Columbian indigenous traditions where death and sacrifice were central cultural preoccupations to explain the meaning and significance of Los Muertos, seeing it as a remnant of ancient Aztec funerary rites. Historians suggest that the Aztecs valued two ceremonies over other rituals – Miccailhuitontli “small feast of the dead” and Hueymiccaihuitl, “great feast of the dead” which may point to why these two days in November have been adopted, dedicating one day to dead children and another to dead adults.
We cannot comment on this history but we did observe how proud the Indigenous peoples of Oaxaca are of their pre-Hispanic origins and traditions. They look back to their ancestors like the Zapotecs and the Mixtecs who were making offerings to the dead before the influence of Catholicism.
In traditional Aztec mythology, Mictlantecuhtli was the lord of the dead and the king of Mictlan, the underworld. He was traditionally depicted as a skeleton or a person with a toothy skull. His wife Mictecacihuatl was the Queen of Mictlan, a place perhaps similar to purgatory.