Katun

The katun is the fourth unit of the Maya Long Count, equal to twenty tuns, or 7,200 days, close to twenty years. The ending of a katun was among the most important of Maya calendrical occasions, marked by the erection of carved monuments and by rituals of renewal, and the Yucatec Maya kept a cycle of thirteen katuns, each bearing prophecies, that gave the passage of these periods a prophetic character. Within the Long Count the katun sits above the tun and below the baktun, each step multiplying by twenty. A Long Count date names how many baktuns, katuns, tuns, winals, and kins have elapsed since the mythic starting point. These are the features of the Maya Long Count, the linear calendar the Classic Maya used to fix events across centuries on their carved monuments.

A Katun is twenty Tun, 7,200 days, or approximately 19.7 solar years, the fourth place in the Long Count. Katun endings, particularly the ending of a Katun on the day Ahau (the last of the twenty Tzolk'in day names), were occasions of major ritual and monumental commemoration in Classic Maya cities, recorded on stelae erected specifically to mark the event, and the roughly 20-year Katun cycle also underlies the later Yucatec U Kahlay Katunob, or Short Count, a colonial-period 13-Katun cycle used by Yucatec Maya chroniclers such as the authors of the Books of Chilam Balam after the practice of carving full five-place Long Count dates had generally lapsed at the end of the Classic period, around the tenth century CE. A Long Count's third-place digit, the Katun count within a Baktun, runs from 0 to 19 before the Baktun place increments.

The katun of 7,200 days, twenty tuns or a little under twenty years, outlived the Long Count itself. After the Classic collapse the full five-place notation fell out of use in the northern lowlands, and what remained in the Postclassic and colonial period was the Short Count, a cycle of thirteen katuns named by the Tzolk'in day on which each ended.

Because a katun of 7,200 days is a multiple of twenty, it always ends on a day Ahau, and because thirteen numbers run against that fixed sign, thirteen katuns exhaust the possibilities before repeating. Thirteen katuns are 260 tuns, roughly 256 years, and the resulting cycle carries the same thirteen-by-twenty shape as the Tzolk'in in a different medium.

The Books of Chilam Balam, written in Yucatec Maya in the European alphabet after the conquest, record history and prophecy by katun in exactly this form, each katun carrying an expected character. The Short Count is genuinely shorter and genuinely ambiguous: a date given only by its katun repeats every 256 years, which is one of the standing difficulties in using those books as chronology.

The Short Count also explains a persistent confusion. A modern account that speaks of a thirteen-katun prophetic cycle is describing the Postclassic and colonial Yucatec system, not the Classic Long Count, and the two run on different principles: one repeats, the other does not. Conflating them produces claims about Classic Maya prophecy that the Classic sources do not contain.