Origins of Día de Muertos (Day of the Dead) in Mexico

The celebration was not "decided" by any single person or decree. It emerged from a millennia-long synthesis of:

1. Pre-Hispanic Indigenous Traditions (Mesoamerica)

• Aztecs (Mexica): Month-long festival Miccailhuitontli (9th month) for children, Huey Miccailhuitl (10th month) for adults — honoring Mictlantecuhtli (Lord of Mictlan, the underworld) and Mictecacihuatl (Lady of the Dead). Offerings: food, flowers (cempasúchil/marigold), incense (copal), paper banners (papel picado), skulls (calaveras).
• Maya: Hanal Pixán ("Food for the Souls") — late Oct/early Nov. Altars with mucbipollo (tamales), candles, photos.
• Purépecha, Totonac, Zapotec, Mixtec: Parallel ancestor-veneration cycles tied to agricultural calendar (harvest).

2. Spanish Catholic Overlay (16th Century Onward)

• All Saints' Day (Nov 1) + All Souls' Day (Nov 2) — aligned with indigenous timing.
• Church co-opted rather than eradicated: moved indigenous observances to Nov 1–2.
• Added: Masses, vigils, cemetery visits, holy water, crosses on altars.

3. Modern National Construction (19th–20th Century)

• Post-Independence (1821): Intellectuals (e.g., José Guadalupe Posada — La Catrina, 1910s) framed it as uniquely Mexican.
• Post-Revolution (1920s): State promoted mexicanidad — Indigenous + mestizo identity. Diego Rivera, Frida Kahlo incorporated imagery.
• 1960s–: Tourism & cultural institutes (INAH, SEP) standardized "canonical" elements (ofrenda tiers, specific foods, parades).
• 2008: UNESCO Intangible Cultural Heritage.
• 2015/2017: Spectre (James Bond) / Coco (Pixar) → global pop culture; Mexico City added massive parade (2016).

Core Elements Today

• Ofrenda (altar): photos, water, salt, pan de muerto, cempasúchil path, favorite foods, candles, incense.
• Cemetery vigils (Nov 1–2) — cleaning, decorating, sharing meals with departed.
• Calaveras literarias — satirical epitaph poems for living.
• Catrina — elegant skeleton figure (Posada → Rivera → global icon).

No one "decided." Millions of families, over centuries, wove Indigenous cosmology, Catholic ritual, artistic expression, and national identity into a living tradition that continues to evolve.