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The Aztec solar year splits into eighteen named twenty day months, three hundred sixty days, and then adds five more that carry no month, no ordinary business and a reputation for danger. The Maya solar year reaches the same structure by the same arithmetic, under a different name, and the atlas records both as neighboring calendrical traditions that arrived at one shared solution rather than one system copying the other.

Eighteen Months and a Remainder

The xiuhpohualli's eighteen veintenas run from Atlcahualo, which opens the year with offerings recorded by Bernardino de Sahagun's informants, to Izcalli at its close. Tlacaxipehualiztli, the second, is dedicated to Xipe Totec, the god of springtime renewal, and its rites are among the best documented of the eighteen. Eighteen months of twenty days is three hundred sixty, five short of a solar year, and the calendar does not stretch a month to cover the gap.

Nemontemi and Wayeb

Those five days are the nemontemi, regarded as unlucky and dangerous, a stretch when ordinary activity, travel and business were avoided because the days fell outside the count of named days proper. The Maya haab calendar answers with the Wayeb, structurally the same five day supplement, under Maya rather than Aztec ceremony and prohibition. The atlas follows David Carrasco's reading of the two as a genuine point of contact between neighboring Mesoamerican traditions, both independently needing a five day remainder to close the solar year and both marking that remainder as religiously distinct from the months around it, while keeping them recorded as parallel structures in related but distinct systems rather than one practice under two names.

Where To Read More

• AtlcahualoVeintenasThe first of the eighteen veintenas, opening the xiuhpohualli.
• TlacaxipehualiztliVeintenasThe second veintena, dedicated to Xipe Totec, among the best documented of the eighteen.
• NemontemiVeintenasThe five nameless days completing the Aztec solar year.
• WayebWayeb (Unlucky Days)The Maya calendar's own structural counterpart to the nemontemi.
• Nemontemi Beside the Maya WayebArticlesThe atlas's own article comparing the two, citing David Carrasco's reading of the shared structure.