Trecenas

This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.

A trecena entry records a specific, named thirteen day period within the two hundred and sixty day tonalpohualli calendar used across Mesoamerica, identified by the day sign and number that opens it, considered for the documented character, patron or omen the tradition assigned to that period as a whole. Cycles of Time and Meaning in the Mexican Books of Fate reads the surviving painted almanacs specifically for how they organize and interpret the trecenas, treating each one as a documented unit diviners actually consulted rather than an abstract mathematical division.

An entry records a trecena's opening day sign and number, its documented patron deity or governing force where the almanac tradition names one, and the character, favorable, difficult, mixed, the sources attribute to a child or undertaking begun within it.

Where different surviving almanacs assign a trecena somewhat different patrons or omens, an entry records that documented variation across sources honestly rather than presenting a single harmonized reading as the tradition's one settled account.

An entry also records which specific painted almanac or codex an assigned patron or omen is drawn from, since the surviving books of fate are themselves distinct physical documents with their own provenance, and naming the actual source keeps a trecena's recorded meaning checkable rather than presented as an anonymous tradition.

This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.

The Getty Research Institute's documentation of the Aztec Calendar Stone, the large carved basalt monument bearing day signs and calendrical bands, records the physical, dated monument that anchors much of what is actually known about how the Mexica themselves depicted their calendar's structure, the tonalpohualli and its trecenas among the systems it represents.

That physical, documented monument matters for a trecena entry because it is a primary source independent of the painted almanacs, direct material evidence for how the calendar's divisions were carved and displayed publicly, and an entry records what the stone itself does and does not depict about the trecena system, distinct from and alongside what the almanac tradition says about individual trecenas.

A trecena entry therefore draws on both kinds of documented evidence where they exist, the almanac tradition's stated meanings for a given period and the calendar stone's own carved record of the system's structure, since the Getty's documentation treats the stone as a real archaeological object with its own excavation and interpretive history rather than a timeless symbol. Both are genuinely separate, complementary sources for the same calendar system.