Not Just One Calendar

There is not just one Aztec calendar, there are two more or less independent systems. One calendar, called the xiuhpohualli, has 365 days. It describes the days and rituals related to the seasons, and therefor might be called the agricultural year or the solar year. The other calendar has 260 days. In Nahuatl, the language of the Aztecs, it is called the tonalpohualli or, in English, the day-count. Most information on this Internet-site refers to the tonalpohualli, which is the sacred calendar.

The tonalpohualli and Aztec cosmology
The tonalpohualli, or day-count, has been called a sacred calendar because its main purpose is that of a divinatory tool. It divides the days and rituals between the gods. For the Aztec mind this is extremely important. Without it the world would soon come to an end. According to Aztec cosmology, the universe is in a very delicate equilibrium. Opposing divine forces are competing for power. This equilibrium is in constant danger of being disrupted by shifting powers of the gods, of the elemental forces that influence our lifes. This struggle cannot be won by any god. The notion that everything ultimately consists of two opposing forces is essential to the Aztec worldview. The world is always on the brink of going under in a spiritual war, a war of gods competing for supreme power. To prevent this from happening, the gods have been given their own space, their own time, their own social groups, etcetera, to rule over. The tonalpohualli tells us how time is divided among the gods.

The system of the tonalpohualli
The system of the tonalpohualli can be best understood by imagining two wheels that are connected to each other. One wheel has the numbers “one” to “thirteen” written on it. The second wheel has twenty symbols on it. In the initial situation, number “one” combines with the first symbol. This is the first day of the tonalpohualli. Now the wheels start moving and number “two” combines with the second glyph. This is the second day. After fourteen days, an Aztec week (trecenas in Spanish) of thirteen days has passed. The wheel with the numbers shows number “one” again. The other wheel now shows the fourteenth symbol. After 260 days, the two wheels have returned to their initial position. The tonalpohualli starts all over again.

Dividing time among gods
A day (tonalli) in the tonalpohualli consists of a number and a symbol or daysign. Each daysign is dedicated to a god. The twenty dayssigns and their gods are successively:

Nr.       Daysign                        God  

1          Cipactli                         Tonacatecuhtli

2          Ehecatl                         Quetzalcoatl

3          Calli                             Tepeyollotl

4          Cuetzpalin                    Huehuecoyotl

5          Coatl                           Chalchihuitlicue

6          Miquiztli                      Tecciztecatl

7          Mazatl                         Tlaloc          

8          Tochtli                          Mayahuel

9          Atl                                Xiuhtecuhtli

10        Itzcuintli                        Mictlantecuhtli

11        Ozomahtli                     Xochipili

12        Malinalli                        Patecatl           

13        Acatl                            Tezcatlipoca

14        Ocelotl                         Tlazolteotl

15        Cuauhtli                        Xipe Totec

16        Cozcacuauhtli               Itzpapalotl

17        Ollin                             Xolotl

18        Tecpatl                         Chalchihuihtotolin

19        Quiahuitl                       Tonatiuh

20        Xochitl                         Xochiquetzal

Each daysign is ruled by a god. The nature of a day is also influenced by its number. More important, each trecenas has a god that rules over that very 13-day period. The twenty trecenas and their associated gods or elemental forces are successively:

Nr.       Trecenas                      God

1          Cipactli                         Ometeotl           

2          Ocelotl                         Quetzalcoatl     

3          Mazatl                          Tepeyollotl        

4          Xochitl                         Huehuecoyotl

5          Acatl                            Chalchihuitlicue

6          Miquiztli                       Tonatiuh 

7          Quiahuitl                       Tlaloc

8          Malinalli                        Mayahuel

9          Coatl                            Xiuhtecuhtli

10        Tecpatl                         Mictlantecuhtli 

11        Ozomahtli                     Patecatl

12        Cuetzpalin                    Itzlacoliuhqui

13        Ollin                             Tlazolteotl

14        Itzcuintli                        Xipe Totec

15        Calli                             Itzpapalotl

16        Cozcacuauhtli               Xolotl

17        Atl                                Chalchihuihtotolin

18        Ehecatl                         Chantico

19        Cuauhtli                        Xochiquetzal

20        Tochtli                          Xiuhtecuhtli

The xiuhpohualli
The 365-day year or xihuitl consists of 18 months (meztli) of 20 days plus five extra (unlucky) days. The last day of the last month of the year gives its (tonalpohualli-) name to the xihuitl. This name is the “Xihuitl” information that is displayed by the calendar. A simple calculation learns that only four daysigns can “bear” (i.e. give their name to) the year. These are Calli, Tochtli, Acatl and Tecpatl for the Aztec calendar. A similar calculation tells us that the number of the xihuitl is raised every year. So year 1-Calli is followed by 2-Tochtli, etcetera. This means that every 52 years (4 times 13) the name of the year will be the same. A combination of 52 years is called a calendar round or xiuhmolpilli (bundle).

Further Additions:

Calendar of the Aztec sun
The Aztec people gave great importance to time, which was registered in two calendars: the one with 365 days, XIHUITL, that was the solar or agricultural one, composed by 18 months fo 20 days, plus five “useless” or “unlucky” days; and the count of the destinies of 260 days, called TONALPOHUALLI, that had more of a divination character.
This calendar was divided in 13 months of 20 days each one. Each day has a name and combines itself rotating with a number from 1 to 13, until compleating the 260 days (13 times 20 = 260). Each day with its numeral has an energetic charge that connects it with the strenght of the cosmos, and it is under the protection of a god, relates itself to a path of the universe and to a color, and has a related omen.
 
The names of the days in Nahuatl are as follows: cipactli, ehecatl, calli, cuetzpallin, coatl, miquiztli, mazatl, tochtli, atl, itzcuintl, ozomatli, malinalli, acatl, ocelotl, cuauhtli, cozcauauhtli, ollin, tecpatl, quiauitl, xochitl. The 18 months of the 365 day solar calendar, received the following names: atlacahualo, tlacaxipehualiztli, tozoztontli, hueytozoztli, txcatl, etzalcualiztli, tecuilhuitontli, hueytecuilthuitli, tlaxochimaco, hueymiccailhuitl, ochpaniztli, pachtontli, hueypachtli, quecholli, panquetzaliztli, atemoztli, tititl, izcalli, and namontemi. The Mexicas believed that the calendar had been invented by Oxomoco and Cipactonal.
The Aztecs divided the solar calendar in 5 periods of 73 days, sorts of seasons which they called cocij: cocij cogaa, it was the time of rain and wind simbolized by the crocodile; cocij col lapa was the time of the harvests represented by the corn; cocij piye chij, was the holy time or holiday, represented by the eagle or the warrior; cocij piye cogaa was the time of droughts and the begining of the calendar; cocij yoocho was the time of sickneses and miseries, represented by the tiger.
THE NAHUA MONTHS AND THEIR GREGORIAN EQUIVALENTS
ATLACAHUALO
Equivalence: february-march
***Image2***
TACAXIPEHUALIZTLI
Equivalence: march
***Image3***
TOZOZTONTLI
Equivalence: April
***Image4***
HUEYTOZOZTLI
Equivalence: april-may
***Image5*** 
TXCATL
Equivalence: may-june
***Image6***
ETZALCUALIZTLI
Equivalence: june
***Image7***
TECUIHUITONTLI
Equivalence: june-july
***Image8*** 
HUEYTECUILTHUITLI
Equivalence: july
***Image9*** 
TLAXOCHIMACO
Equivalence: August
***Image10***
HUEYMICCAIHUITL
Equivalence: august-september
***Image11*** 
OCHPANIZTLI
Equivalence: september
***Image12*** 
PACHTONTLI
Equivalence: october
***Image13*** 
HUEYPACHTLI
Equivalence: october-november
***Image14*** 
QUECHOLLI
Equivalence: november
***Image15*** 
PANQUETZALIZTLI
Equivalence: december
***Image16*** 
ATEMOZTLI
Equivalence: december-january
***Image17*** 
TITITL
Equivalence: january
***Image18*** 
IZCALLI
Equivalence: february
***Image19*** 
NEMONTEMI
Equivalence: february
***Image20***