Walking with both counts

Two wheels, not one

What is called «the Aztec calendar» is two counts running at once, and confusing them is the commonest error in the subject.

The solar year, the xiuhpohualli: eighteen veintenas of twenty days, plus the five nemontemi. It governs what is done: the sowing, the harvest, the feast, the tribute. It is the calendar of work and of the agricultural cycle.

The count of days, the tonalpohualli: twenty trecenas of thirteen days. It governs what is said of each day: which energy rules it, what omen the sources attribute to it, what was kept and what was not.

Neither is enough alone. A complete Mexica date carries both: the veintena it falls in and the trecena that crosses it. Walking with both is what in Nahuatl is called nenemi.

Why they never coincide

Thirteen and twenty share no divisors, so the same pair of veintena and trecena takes a long time to come back.

And that is not a defect of the system: it is its engine. From that mismatch come the two hundred and sixty days of the count, and from crossing it with the three hundred and sixty-five of the solar year comes the cycle of fifty-two years.

The Mexica calendar is built on numbers that do not fit, on purpose.

What falls on any given day

Several things can come together on the same day, and almost never all of them: the numeral and the sign; the veintena and the energy the sources dedicate it to; the trecena and the energy that rules it; the bearer of the year, one of the four signs that can name a year — Ácatl, Técpatl, Calli or Tochtli; the Lord of the Day, of thirteen, and the Lord of the Night, of nine; and sometimes a feast, if the sources place one there.

The part almost nobody tells

There are days the sources say nothing about.

Of the twenty trecenas, nine carry an omen of the day — what was done, what was kept, what descended. The other eleven do not. And the five nemontemi fall outside every veintena.

That is not a gap to be filled: it is the state of the record. Sahagún collected what he collected, and where he collected nothing, there is nothing.

A system that always has something to tell you about any day is not reading the sources: it is inventing. That is the difference between this and a horoscope, and it shows precisely in the silent days.

What this is not

It is not astrology. There are no twelve houses, no planets assigned to characters, no birth chart. The tonalpohualli was a divinatory count — saying it was not would be special pleading — but its apparatus is another: signs, numerals, energies and directions, not celestial bodies.

And it is not a system of personal prediction. What the sources attribute to a day is what happened or suited that day, not what will happen to whoever reads it. What is said of whoever is born on a day is another matter, and lives in the reading of the tonalámatl.

Questions that reach this page

How did the Aztec calendar work in daily life? With two counts at once: the solar year of eighteen veintenas, which governs labours and feasts, and the 260-day count, which governs what is said of each day.

Why are there two Mexica calendars and not one? Because they count different things. One follows the agricultural year; the other the divinatory cycle. They run together and never coincide, and from that mismatch come the 260 days and the 52-year cycle.

What does nenemi mean? «To walk», in Nahuatl. Here it names walking with both counts at once, which is how it was lived.

Do the sources say something about every day? No. Nine trecenas of twenty carry an omen of the day; the other eleven do not, and the five nemontemi fall outside every veintena. Where the source is silent, nothing is filled in here.

Is the Aztec calendar a horoscope? No. The tonalpohualli was a divinatory count, but it is not astrology: no houses, no planets, no birth chart. And a system that always has something to say about any day is not reading sources.

What is a veintena and what is a trecena? A veintena is twenty days of the solar year, of which there are eighteen. A trecena is thirteen days of the divinatory count, of which there are twenty. It is the commonest confusion in the subject.

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