The Mesoamerican cultures of the pre-Conquest Aztecs and Maya appear dauntingly foreign to Western eyes, with their sacrificial rituals, vigesimal (base twenty) counting systems, and names like Huitzilopochtli. A few authors, though, have tackled the challenges of these cultural frameworks, producing fantasies which stand out against the often-criticized homogeneity of fantasy settings. Marella Sands, for example, has written two novels, Sky Knife and Serpent and Storm, which are set in the ancient Mayan world; in these works, human sacrifice is not only necessary but sometimes good. Alexander C. Irvine's novel A Scattering of Jades brings Mesoamerican ideas further forward in time by telling a story of Aztec rituals in nineteenth-century America. And finally, Pat Murphy's The Falling Woman takes ancient material up to the present day by centering on the recent end of a Mayan calendrical cycle.
In ancient Mesoamerica, measuring time was a complex business, often involving multiple different calendars at once. Finding explanations of them online is relatively easy, but those explanations rarely go beyond the math—one tun is 360 days, one katun is twenty tuns, and so on. Such dry equations give very little sense of the cultural meaning of the calendars, though, and of how ancient Mesoamericans viewed time. Pat Murphy's novel hints at the underlying meaning, but these topics are still largely unexplored in fantasy fiction, and they offer rich possibilities for a writer interested in doing something different.
The Solar and Sacred Cycles
One of the multiple calendars used in ancient times is a familiar-looking 365-day solar year most commonly called the haab. This consisted of eighteen months of twenty days each, with a "left-over" five-day month between the end of one year and the beginning of the next. Depending on which source you consult, the days of each month were either numbered 1 to 20, or 0 to 19; some of the confusion results from the fact that the final day of one month was also considered the "seating" of the next, where the handover took place. Likewise, the five "extra" days are the seating of the new year. Months and years do not overlap their predecessors, but scholars have differed in which set of numbers best reflects this idea.
The haab does an adequate job of measuring the length of our planet's journey around the sun, though it lacks the minor correctional adjustments of the modern Western calendar (such as leap years). It would therefore seem to be sufficient; what does one need another calendar for?
There was another calendar, though, and in some parts of Central America it is still in use. This second system is most commonly known as the tzolkin, and it lasts for 260 days, a length whose importance is not at all clear. Scholars have made attempts to link it to cycles such as the human gestation period, but no one knows for sure why the number was chosen.
It was very widespread in ancient Mesoamerica, beginning as far back as the Olmec culture; this page, for example, lists day names from Nahuatl, Zapotec, Mixtec, and Yucatec Mayan. Barbara and Dennis Tedlock, a husband-and-wife team of anthropologists, have done a great deal of research on the use of this calendar among the K'iche' Maya in Guatemala. What all of these calendars have in common is a structure consisting of twenty day names and thirteen day numbers, fitting together in an interlocking cycle that lasts for 260 days (the lowest common multiple of twenty and thirteen).
The tzolkin does not have a designated starting point, the way the Gregorian calendar starts on January 1st. The day numbers may tick up from one to thirteen, and then start over again, but the day names, although they exist in a particular order, do not have a beginning or an end. There is no point in the tzolkin that is considered the "start" among those modern peoples still using it, and no evidence that there was a "start" in the past. A quick demonstration will help to illustrate how it works in practice. Assume you choose to begin your count with the day 1 Jaguar.  It will then go like this:
At that point, having reached the end of the number cycle, you start it over at 1, while continuing through the day names.
Now you have used all twenty day names, so that cycle begins again, while the numbers go on: 8 Jaguar, 9 Bird, and so on. The combination 1 Jaguar will come around again 260 days after its first occurrence. The tzolkin is used for divination and the timing of certain rituals, which I will discuss later.
As it happens, the tzolkin and the haab fit together in such a way that the new haab year always begins on one of four day names in the tzolkin (though the numbers will cycle over time). If the haab were 360 days long, then the beginning of the haab would always fall on the same tzolkin day name; 360 is evenly divisible by 20. Since the haab is 365 days long, though, each new year will fall five days further along in the tzolkin names, and since there are twenty day names (evenly divisble by five), only four day names will coincide with the beginning of the haab. In the K'iche' naming system, those days are Wind, Deer, Tooth, and Thought, and are referred to as "Year-Bearers."
The Short and Long Counts
From here the ancient Maya added on even more calendars. One, called the Short Count, combined the tzolkin and the haab with Venus' 584-day cycle to produce periods of 13, 52, and 104 years (52 and 104 being four and eight times 13, respectively). The numbers four and eight, like thirteen and twenty, recur frequently in Mesoamerican counting.
More famous than the Short Count, though, is the Long Count, with its dates that look more like IP addresses than any Western system of time. It measures days from a "zero date" (August 9th, 3114 B.C. in our calendar ), and ticks upward like an odometer. The basic unit of the Long Count is the tun or "stone," a 360-day year (not to be confused with the 365-day haab; the tun lacks the 5-day month). Twenty tuns make a katun; twenty katuns make a baktun. There are even larger units than that: twenty baktuns make a pictun, and twenty pictuns make a calabtun.
At this point we are measuring time in units of approximately 160,000 years—far longer than any human history. But the notation of the Long Count rarely goes beyond the baktun level; it usually consists of notations for the baktun, the katun, the tun, the uinal (month) and the kin (day). This is then followed by the tzolkin and haab dates (e.g. 3 Jaguar 2 Kankin). The thirteenth baktun will end on December 21st, 2012.  Some scholars claim the Maya viewed this as the end of this round of creation, but there are inscriptions which give the Long Count date with as many as twenty units above the katun level, all of them still sitting at 13 (which is the beginning, rather than the end, of their cycle), so this apocalypse scenario may or may not be true.
As a slightly more practical example, in the Long Count, August 30, 2004, would be written 18.104.22.168.5 11 Snake 8 Mol. The first five numbers are the Long Count itself, while "11 Snake" (or Chik'chan, in Yucatec, for instance) is the tzolkin date and "8 Mol" is the haab.
One obvious question is what the Maya could possibly have needed such a complex calendrical system for. It certainly wasn't to accurately model the solar year; the haab does that all on its own, far better than the tzolkin or the tun-based Long Count. Why such odd systems, and why so many of them all at once? Nor did the Mayan obsession with time end with the systems I have described already. A quote from Linda Schele and David Freidel's excellent book A Forest of Kings illustrates how complexly a single day could be described:
January 1, 2000, will fall on 9 Ahau in the 260-day Sacred Round [tzolkin] and the eighth day of Kankin in the 365-day haab. The Calendar Round [tzolkin + haab] designation is 9 Ahau 8 Kankin, which will be ruled by the third Lord of the Night. On that day, the moon will be 25 days old. Venus will be 133 days after inferior conjunction; and Jupiter will be 69 days, and Saturn 51 days, after opposition to the sun. It will be 2 years, 50 days after the beginning of the 2,282nd quadrant of the 819-day count in which the white God K will rule the north sky. And finally, that day will fall on the 1,867,260th day since the Maya zero date, expressed in the Maya Long Count as 22.214.171.124.0. (p. 83)
Discussing the importance of celestial movements would require another entire article and a great deal of astronomical knowledge, but this quote also hints at what lies behind the math—the meaning that ancient Mesoamericans invested in their calendars.
Moving Beyond the Math
For example, why the cycle of twenty? Why does that number recur so frequently in the various systems (twenty day-names in the tzolkin, twenty days in the haab month, twenty tuns to a katun)? Surviving texts and archaelogical evidence point to human beings having twenty digits—ten fingers and ten toes. Because of this, Mesoamerican counting was vigesimal, rather than decimal (base ten).
The cycles weren't just mute units, either. The gods influenced the cycles, as Schele and Freidel's references to "rule" indicate. It can be difficult, looking at ancient inscriptions and the few surviving books, to sort out exactly what gods ruled over which parts of the Long Count, but the tzolkin is easier to understand, because it is still in use among some Mayan peoples today.
The day names, to the K'iche' Maya, are not simply identifying tags, the way our own weekday names are; they are, perhaps, more comparable to the meanings that lie behind our weekdays. If instead of Wednesday, Thursday, Friday, and so on, we were to say Woden's Day, Thor's Day, and Frey's Day, we would be coming closer to the tzolkin's meaning. The day names in that system are also the names of divine beings, who rule over the days in turn. And, to make this even more complex, each Day Lord is not one but thirteen, so that you'd be less likely to speak of Lord Thought than Lord One Thought, Lord Seven Thought, or Lord Thirteen Thought.
Each Day Lord, unsurprisingly, has a particular character, which influences the days he rules over (and the people born on his days). It is oversimplifying, though, to describe them as good or bad, lucky or unlucky. Much depends on context. For example, a day might be bad for travel and business deals, but good for dealing with family, or it might be good for some family things (like honoring the ancestors) and bad for others (like getting married). The number also influences the "face" of the day; low numbers are "gentle," middle numbers "indifferent," and high numbers "violent." Lord One Deer and Lord Thirteen Deer are at the opposite ends of the spectrum of Deer's possible faces. Furthermore, as mentioned above, the haab will always begin on one of four day-names; the Day Lord currently serving as Year-Bearer also puts his stamp on any day that follows. In a year ruled by Lord Wind, therefore, many things will be affected by his crazy, violent character.
Daykeepers and Divination
Among the K'iche', and among some of the neighboring indigenous groups, there is a class of people called "daykeepers," who have a two-fold job. One is that they carry out small rituals on specific days in the tzolkin—for example, honoring the ancestors at the family shrine. In this sense, then, they "keep the days." These rituals are performed in specific locations, related to the numbers of the days; there is, for example, a "One's Place," for one-numbered days, and an "Eight's Place," for eight-numbered days.
The tzolkin is not just a background force, though, making days favorable or unfavorable for certain activities. It can also be used more directly, to divine answers to specific questions that a petitioner brings to a daykeeper. In order to do this, the daykeeper questions the Day Lords themselves, counting out from the current day. The length of the count is determined by a handful of seeds taken from the diviner's bag and sorted into piles of four; the daykeeper counts one day to each pile, and goes through them a set number of times. The responses come in the form of "lightning," a tingling in the body of the diviner as he says the name of the Day Lord; he (or she; married couples are often initiated as daykeepers together) will then interpret the meaning based on the location and direction of the lightning. The interpretive system is complex. The right side of the body indicates the male, while the left indicates female; the front is the future or descendants, while the back is the past or the ancestors; trained daykeepers can determine even smaller details from the nuances of the lightning, such as whether an ill person will recover or worsen.
The daykeeper, then, combines the information given by the lightning with the nature of the Day Lord currently in question. This nature is marked with a series of mnemonics, based in a punning fashion on the name of the Day Lord himself; for this reason, Barbara Tedlock argues that it does not make sense to translate the day names, because doing so loses the connection to the mnemonics while failing to capture the full sense of the day. To give one example, for the day Tz'i', which can be translated as "dog," she gives the following mnemonics: "tz'ilonic ('to be dirty, soiled, stained, impure'—with the connotation of making love either to the wrong person or at the wrong time or place), tz'iyalaj tzij ('jealous words' between husband and wife), and catz'iyaric ('it isn't certain')." (p. 116) The day Tz'i' is generally bad for ritual purposes, and in divination it can indicate adultery or other sexual misconduct, which may be causing friction within a marriage. Someone born on a Tz'i' day is expected to be weak, uncertain, and prone to inappropriate sexual relations.
So much depends on context that no meaning is immediately straightforward. If the petitioner were, for example, asking the daykeeper about his prospects for marrying a certain woman, and the day Eleven Tz'i' were to trigger a response in the daykeeper, it might indicate that the woman would be prone to adultery and is therefore bad marriage material. If the lightning were in the back of the right side of the daykeeper's body, though, it would refer to a male ancestor, not the woman herself; perhaps she's fine, but there is a problem with her father. The diviner would then question the Day Lords further, to chase down just what the issue is, and whether it can be resolved.
A Philosophy of Time
All of this only barely scratches the surface of the meaning of time in Mesoamerican thought. Some of it is quite frankly mind-bending. For example, philosophically, time and space are conceived of as the same thing; the space-time continuum is not merely an innovation of modern physics. A Maya text called The Book of Chilam Balam of Chumayel contains in it a story called "The Birth of the Uinal," which describes the creation of the twenty day-name cycle as the story a man journeying down the road. Uinal and the term for man, uinic, come from the same root word, and Roberta H. Markman and Peter T. Markman, in their book The Flayed God, introduce "The Birth of the Uinal" by saying, "The basic metaphor underlying this myth thus brings together the image of the birth of time and the origin of man in the same encapsulating moment. Nothing exists until movement, the essential sign of life, makes its appearance." (pp. 97-8) Movement through time, movement through space, movement of mankind; all of these concepts are intertwined quite profoundly.
Another aspect of time comes about when we consider the motif of "previous ages" among Mesoamerican cultures. Both the Maya and the Aztecs believed there had been other epochs and other races before the current one, each ending in some kind of cataclysm; among the Aztecs, these were referred to as "suns," and the age in which we live now is the Fifth Sun. The relationship of these various suns to each other can be seen two ways, as Markman and Markman describe:
Significantly, however, [the suns'] progression can be seen in both linear and cyclical terms. If one takes a 'historical' view and sees the Fifth Sun as the last stage in a progression, the final age of the world, the movement is conceptually linear. But if, in contrast, one takes a 'mythic' view, seeing the repetition of the ages as a metaphor for the fundamental reality of death and rebirth, the movement is cyclical. . . . In addition, it is important to realize, in the light of what we know about the essence of Mesoamerican spiritual thought, that the ages existed in a complex pattern of juxtaposition to each other, an essentially quadripartite pattern in which the Fifth Sun served as the center or hub of the cosmos. According to Mircea Eliade, such a center is the ultimately sacred place where the planes of spiritual and material reality intersect, the place where the sacred manifests itself in its totality. (p.74)
To put the latter description in more visual terms, the cosmos is conceived of as a quincunx, a cross whose arms are of equal length, and whose center takes the same importance as the arms. The four suns are at the ends of the arms; the Fifth Sun—our age, our reality—is the center. This arrangement has particularly interesting implications for an apocalypse scenario, as the authors go on to say:
The logic of the myth suggests that there could never be a sixth sun because the Fifth Sun is the synthesis of the quadrants of reality and their qualities as well as a synthesis of the other four suns and would therefore not be subject to the great law of continuous change through destructive catastrophe. (p. 77)
So you could, perhaps, take two different views of the cosmos and the possibility of apocalypse. If the suns are linear and sequential, then the Fifth Sun, like its predecessors, could undergo a catastrophe and be replaced. If, on the other hand, the suns are cyclical and spatially related to one another, then the Fifth Sun might be exempt from that fate—but, if it were to end, there could never be a Sixth Sun to follow it. The quincunx has only five points of importance.
A speculative fiction writer looking for a change of pace from familiar European cultural models has plenty to draw on here. A calendar is, fundamentally, a means of organizing humanity's perception of and relation to time. A different calendar, therefore, can be far more than just window dressing on a story; it can totally reorganize some of the basic principles of the setting. If time is personified in divine beings, how would humans relate to them? What could be done with their favor and aid—and what would happen if they were angered? If time is cyclical in this kind of complex fashion, and time and space are related, what might be possible in such a world? Instantaneous travel between one Eight's Place and another Eight's Place on any day numbered eight? Travel through time by travel through space? Echoes of the past into the present, as certain dates come around again? Pat Murphy plays with this exact idea in The Falling Woman, with the end of a particular Long Count cycle. A creative enough approach might find a way around such staples of time philosophy as the "grandfather paradox," which are dependent on certain conceptions of time. The possibilities are many, and I hope to see more authors pursue them.
If any of this has caught your interest, there are a number of books which go into the subject in greater detail (I've only scratched the surface of them in this article). The two most influential for me have been the works of the Tedlock couple. Dennis Tedlock's Breath on the Mirror: Mythic Voices and Visions of the Living Maya is a beautifully written ethnographic work on the modern K'iche', exploring their stories and myths and how those relate to their daily life. It provides a comprehensible introduction to the ritual calendar, and then from there, you can move on to Barbara Tedlock's Time and the Highland Maya, which describes the roles and practices of K'iche' daykeepers in much greater detail.
For a more general work on the ancient Maya, I recommend A Forest of Kings: The Untold Story of the Ancient Maya, by Linda Schele and David Freidel; it draws heavily on archaeological and textual evidence to describe ancient Mayan life, and even contains fictionalized vignettes of key events in Mayan history (particularly useful to a writer more interested in atmosphere than scientific verification, though Schele and Freidel do try to be accurate). That book gave me a good sense of the Mayan structure of space, particularly ritual space, and its relationship to time.
For the more philosophical issues of time, look to The Flayed God: The Mesoamerican Mythological Tradition: Sacred Texts and Images from Pre-Columbian Mexico and Central America, by Roberta H. Markman and Peter T. Markman. The book covers much more than time, of course, partly because the concept of time is so inextricably linked to so many other issues.
And finally, although the Markmans' book contains excerpts from a great many texts (and, in the case of shorter ones, the texts in their entirety), no listing of this kind would be complete without mentioning the Popol Vuh, the most famous of the few surviving Mayan ancient works. It is the story of the creation of the world, as told by the ancient K'iche' Maya; Dennis Tedlock has done a translation of it, and it is well worth reading.
"Mesoamerican Calendars," by Marie Brennan, is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.
If you redistribute this article, please include a link to
 Thanks to the research of the Tedlocks, I am most familiar with the K'iche' names for the days, and will be using them—in translation—throughout this article.
 There are two competing theories for how to translate Mayan Long Count dates into the Gregorian calendar, which differ from each other by two days; the other theory would make that date August 11th.
 or December 23rd; the 21st will be the winter solstice, and there's a good argument here for why that might be the right date.