Perhaps the greatest intellectual achievement of the Mayans was their complex calendar system. They used two calendars simultaneously: 260-day and 360-day. A shortened version of the Mayan calendar inherited from the Mayan civilization of the Oaxaca Valley of Mexico, which began to record dates on this calendar about 600 BC. In this calendar there were 20 personal days, each of which was repeated 13 times, a "short year" of 260 days was called tzolkin.
The calendar was not only a measure of time, but also a guide to the future. As a leading Mayan historian, Professor Michael Coe explains:
"Each day had its own omens and associations, and the inevitable change of 20-day cycles served as a kind of predictive machine that predetermined the fate of the Mayans and all other peoples of Mexico.
Even today, there are "calendar priests" in the Guatemalan hills who can give a name to any day in the 260-day cycle.
How was this "short year" related to the present year? Seventy-three 260-day cycles (18,980 days) were 52 real years, and from that point on both calendars were synchronized again. Therefore, a calendar cycle was invented that was repeated every 52 years.
The calendar cycle, with a 52-year renewal period, looks very short for a culture with such outstanding mathematical abilities. The reason for its creation can be found in the structure of the calendar of the so-called Long Mayan Account. Their daily calendar consisted of 18 months of 20 days each. With five additional "unhappy" days at the end of the year, which caused superstitious horror, the annual cycle reached 365 days and was compared to the solar year. Presumably, since this number did not fit into their 20-page numbering system, the Mayans ignored the five extra days and adhered to a 360-day period (tuna) for their Long Account.
The Long Account consisted of a series of periods, counting in ascending order, starting from one day (kinu.
20 kin = 1 dunal (20 days)
18 dunes = 1 tunnel (360 days)
20 tons = 1 katun (7200 days) = 19.7 years
20 katunov = 1 bactun (144,000 days) = 394.3 years
In the Great Cycle there were 13 agguns - 1,872,000 days, or about 5130 years old. The countdown dates back to August 13, 3114 BC, when the present Great Cycle or the World Era began. It was believed that this date symbolized the creation of the world or the appearance of gods, but it is more likely that this is a mythical date of the Mayans themselves, as the texts contain inscriptions about the acts of the gods, which relate to events that occurred in earlier times.
The end of the current Great Cycle is scheduled for December 23, 2012. On this day, according to the Mayan prophecy, the whole world, as we know it, will perish from the great flood. However, this is not the only element of the prophecy contained in the Great Cycle, because it was believed that the events are repeated regularly. Each katun was named after the day it ended, and because of the peculiarities of the design of the calendar only 13 different days could reach the end of the katun. Therefore, after each period of 260 tones (93,600 days, or just over 256 years), the same name of katun began, lasting just under 20 years. Over time, each of the thirteen katuns acquired its own reputation. Ten of them were considered "bad" - apparently, the ancient Mayans held pessimistic views of the world around them. One of the worst was Katun 8 Ahow, which signalled discord and political change.
Earlier cycles of this Katun were also marked by dramatic events. Around 278, the center of power shifted dramatically: the southern Mayan civilization collapsed after the catastrophic eruption of the Ilopango volcano in El Salvador, while the Mayan cities in the lowlands gained an advantage. 25b years later (534 AD), at the corresponding point of the next cycle, the fate of the great city of Tikal was dramatically changed. There were internal strife, perhaps peasant revolts, accompanied by widespread deliberate damage to public buildings and monuments. The reason for the catastrophe, apparently, was the complete defeat of Tikal in the war with Karakol - his aggressive neighbor on the territory of present-day Belize. Only in the middle of VII century, the city-state of the southern lowlands recovered from this shock. Finally, in 790, the last standing stone was erected in Tikala, marking the beginning of the next cycle. Taking into account the catastrophes that took place in the previous 256-year intervals, the crisis could be expected with confidence. And it came, but this time it was the beginning of the end for the Mayan civilization on the lowlands.