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The sky and the cycles

The xiuhmolpilli

The binding of the years — 52

12345678910111213TochtliÁcatlTécpatlCalli
The fifty-two years of the round: four bearers by thirteen numerals.

What it covers

The fifty-two-year cycle in which the two counts come back into step, and the New Fire that closed it.

The full entry is in Spanish, and here is why

What you have read above is this project's own summary of the xiuhmolpilli. The full entry — the part that rests on the sixteenth-century sources — has not been translated, and that is a decision rather than an omission.

We chose not to touch the primary text. Those sections quote Sahagún, Durán and the codices in their own words, often in sixteenth-century Castilian. A quotation carried across stops being a quotation: it loses the register, the ambiguity and the exact wording someone might want to check against a facsimile.

In Spanish the entry carries:

Read the full entry in the original Spanish → Nahuatl names and terms are identical in both versions.

How to cite this page

Alma Mexica, «The xiuhmolpilli», The sky and the cycles. Revised 2026-09-17. https://almamexica.org/en/cycle/xiuhmolpilli/

Questions that reach this page

What is the Aztec 52-year cycle?

The xiuhmolpilli, literally «the binding of the years». Four year-bearer signs — Acatl, Tecpatl, Calli and Tochtli — combined with thirteen numbers give 52 years without repeating, and when the round closed the New Fire ceremony was held.

What was the Aztec New Fire ceremony?

The rite held every fifty-two years, when the xiuhmolpilli closed. Every fire was put out and a new one kindled on the hill of Huixachtlan. The last one the sources place with certainty was in 1507, in the year 2-Acatl.

Why is the Aztec cycle 52 years long?

Because 365 and 260 only line up again after 18 980 days, which is exactly 52 solar years and 73 rounds of the 260-day count. It is the least common multiple of the two counts, so it could not have been any other number.