"The Aztecs: their numbers, their days, and their gods"
Version in Spanish: Los Aztecas: sus números, sus días y sus dioses

J. Zimmerman

(January 2004; class of Gabriela P. De Finn)

Here I summarize the numbers, the days, and the Gods of the Aztecs.

The first signs of the Aztecs in the Valley of Mexico was in 1256 A.D. (7) Aztecs arrived at Mesoamerica and adapted some of the culture that existed, specially of the Toltec inhabitants already established in the Valley of Mexico. Consequently, some symbols of the Aztecs are similar to the previous cultures.

1. The Aztec Numbers

The Aztecs wrote using pictorial writing, that contained symbols similar to those used by the Chinese or by the ancient Egyptians. All the symbols were drawings like ideogramas. Each object expressed its own nature, and also the related and underlying ideas.

Their numerical system counted in twenties. Basic numbers had ideogramas or Aztec glyphs. These were the numbers for the daily and common use: (9), (2)




A point or occasionally a finger or the same object.


Two or more points or fingers or the same objects.


A flag (pantli or cenpantli)

(20 x 20)

A hair (9). or one feather of a bird or a fir (2).

(20 x 20 x 20)

A bag (or xiquipilli or cenxiquipilli) or a bolsa adornada adorned with tassels. One imagined that it contained 8,000 beans of cacao.

For example, about 400 blankets of the cotton were represented by the hieroglyphic symbol for a blanket of the cotton underneath a symbol for 400.

These common numbers appeared in Codices, to show the tributes that the Aztecs (as the Mafia) demands. (4)

Nevertheless, Osorio (7) informs that there was not only one numeration, but three:

The numerals with astronomical values were developed in ceremonial centers. The Aztecs used them to transmit their astronomical knowledge. The system is based on the astronomical observations. Only the people with knowledge could decipher these numerals. Each of the symbols has its astronomical interpretation.

For example, Osorio (7) reports a symbol that formed with a picture with five points; it said that to this form "represents the 8, because five years of Venus are equivalent to eight years of 365 days of the Earth".

2. The Aztec Days

The Aztecs assigned names with their respective pictograms to the 20 different days. Sometimes, different references suggest names that are a little different but essentially the same, or they suggest different pictograms . For example, here is an image of Cóatl (the serpent), which is the symbol for the fifth day: (8)

una imagen por Cóatl (serpiente)

The 20 names and pictogramas by the 20 days are (from (5) on the web, which shows a copy of an illustration in the book of Valliant (9)):

Los 20 nombres y pictogramas por los 20 días

The Aztecs had two calendars, the solar calendar and the lunar calendar. In this article, I follow Valliant (9), and use "month" for the group of 20 days in the solar calendar and "week" for the group of 13 days in the lunar calendar.

  1. The solar, worldly, and civil calendar has 365 (or 366) days. This year received the name of xiuhmilpilli. The solar year had 20 days in each of 18 months to the year. That total was 360 days. In order to complete the 365 days of the solar year they added at the end of the year the 5 (or 6) days (called nomentemis) that dedicated to the pleasure and the diversion.
  2. The lunar, ceremonial, and religious calendar has 260 days. This year received the name of tonalpohualli in náhuatl ("cuenta of días"). This sacred year contained 13 days in each of the 20 weeks. A cycle of 20 weeks was 260 days (13 multiplied by 20) and thus created a basic unit.

The first sign of a day is "Lagarto". For that reason the first day of tonalpohualli (the lunar calendar) is called "1 Lagarto" ; this is the combination of the first number with first of the twenty signs. Thus, the date is counted consecutively (we recommence at 1 after we reach 13):

Week 1 1 Lagarto (Lizard), 2 Viento (Wind), 3 Casa (House), 4 Lagartija (Small lizard), 5 Serpiente (Serpent),
6 Muerte (Death), 7 Venado (Deer), 8 Conejo (Rabbit), 9 Agua (Water), 10 Perro (Dog),
11 Mono (Monkey), 12 Hierba torcida (Twisted Grass), 13 Caña (Cane)
Week 2 1 Jaguar (Jaguar), 2 Águila (Eagle), 3 Zopilote (Buzzard), 4 Movimiento (Movement), 5 Pedernal (Pedernal),
6 Lluvia (Rain), 7 Flor (Flower),
8 Lizard (House), etcétera.

Then, the first month of tonalpoalli began with day number one, "1 Lizard". The second month began with the day that was called "1 Jaguar". The last one of the twenty days (flower) was the seventh day of the second month.

Then the series again continued with Lizard: "8 Lizard".

The names of the 20 lunar weeks meant for each one the following one: (1)

1 flecha (arrow) 2 tigre (tiger) 3 águila (eagle) 4 cuervo (crow) 5 los cuatro movimientos del sol (the four movements of the sun)
6 pedernal (pedernal) 7 lluvia (rain) 8 flor (flower) 9 serpiente armada de arpones (serpent armed with harpoons) 10 Ehecatl (el gran dios Ketzalcoatl en figura de viento) (the great God Ketzalcoatl in the shape of the wind)
11 casa (house) 12 lagartija (small lizard) 13 culebra (snake) 14 muerte (death) 15 venado (deer)
16 conejo (rabbit) 17 agua (water) 18 perro (dog) 19 mona (monkey) 20 hierba (grass)

The two calendars (solar and lunar) appear together in many civilizations, like that of the ancient British as seen at Stonehenge. For the Aztecs, like for the ancient British, the combination of both calendars produced a cycle of 52 years. Gonzáles (6) demonstrates how the solar calendar is interlocked with the lunar calendar, to create the cycle of 52 years.

As for all calendars calculated in the basis of the Earth's rotation around the sun, the Aztec calendars are inexact. Sometimes corrections and adjustments were made.

3. The Aztec Gods

Fernández (3) enumerates almost 200 Gods and goddesses. And the text of Fernandez is not complete.

The primogenitor God is called Moyocoyani, "he that created himself". He was invented to constitute the principle. The opposites occured in him, such as spirit and matter, fire and water, masculine and feminine, the positive and the negative. For that reason, the God is called Ometeotl, "God of duality", creator and destroyer.

This supreme principle appears in a series of manifestations, like independent Gods, but they are only the phases and the forms of the single principle.

In detail "simultaneously manifested like" are Ometecuhtli, "Lord of Duality", and Omecihuatl, "Lady of Duality". They are the Creative Pair, Gods of creation and of life. Also they appear simultaneously like Michtlantecuhtli, "Lord of Death" and Michtecacihuatl, "Lady of Death".

The creative pair procreated four children called:

There are many more Gods. A God was associated with:

For example the Gods that assign themselves to the days first are these: (9)

Day Name
del día
Numen Possible significance
1 Lagarto (crocodile) Tonacatecuhtli Gentleman of Our Subsistence, creative God.
2 Viento (Wind) Quetzalcóatl Serpent, Plumed, God of Skies, God of Knowledge (del Saber)
3 Casa (House) Tepey óllohtli Heart of the mountains, an Earth God
4 Lagartija (Small lizard) Huehuecóyotl old Coyote, Chismoso
5 Serpiente (Serpent) Chalchihuitlicue Lady of the bejeweled mantle, Goddess of Water
6 Muerte (Death) Tecciztécatl The one of the marine snail, God of the Moon.


  1. Anonymous. El Calendario Azteca. http://www.elalmanaque.com/Calendarios/azteca.htm Spain. 2003.
  2. Araujo, Mario. Libros, documentos y escritura Azteca. http://www.azteca.net/aztec/nahuatl/writingsp.html. USA. 1996
  3. Fernández, Adela. Dioses Prehispánicos de México, 1992.
  4. Ferras, Víctor M. Castillo, and others. La Matrícula de Tributos in Arqueología: Edición Especial Numero 14. Mexico. 2003.
  5. Fondo de cultura económica, México. Códice borbónico. (Some notes are here. http://hemi.ps.tsoa.nyu.edu:8000/course-nyu/conquest/materials/images/html/borcalendar.html ). Mexico. 1991.
  6. Gonzáles, Federico. El Simbolismo Precolombino. Argentina.2003.
  7. Osorio , Víctor Larios. Sistemas numéricos en el México prehispánico, Magazine Eureka, No. 15, pages 26-39. (Also http://www.uaq.mx/matematicas/vlarios/xart08.html.) Mexico. Marzo 2000.
  8. Saad, Miguel Navarro. Entre los calendarios gregoriano y azteca. www.uaq.mx/ingenieria/publicaciones/calendarios/calazt.html. Mexico. 2000.
  9. Valliant, George C. The Aztec Civilization. USA. 1941.

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