section_path: Calendar
section_name: Calendar
paragraph_text: Calendar
  
  The Maya calendrical system, in common with other Mesoamerican calendars, had its origins in the Preclassic period. However, it was the Maya that developed the calendar to its maximum sophistication, recording lunar and solar cycles, eclipses and movements of planets with great accuracy. In some cases, the Maya calculations were more accurate than equivalent calculations in the Old World; for example, the Maya solar year was calculated to greater accuracy than the Julian year. The Maya calendar was intrinsically tied to Maya ritual, and it was central to Maya religious practices. The calendar combined a non-repeating Long Count with three interlocking cycles, each measuring a progressively larger period. These were the 260-day tzolkʼin, the 365-day haabʼ, and the 52-year Calendar Round, resulting from the combination of the tzolkʼin with the haab'. There were also additional calendric cycles, such as an 819-day cycle associated with the four quadrants of Maya cosmology, governed by four different aspects of the god Kʼawiil.
  
  The basic unit in the Maya calendar was one day, or kʼin, and 20 kʼin grouped to form a winal. The next unit, instead of being multiplied by 20, as called for by the vigesimal system, was multiplied by 18 in order to provide a rough approximation of the solar year (hence producing 360 days). This 360-day year was called a tun. Each succeeding level of multiplication followed the vigesimal system.
  
  The 260-day tzolkʼin provided the basic cycle of Maya ceremony, and the foundations of Maya prophecy. No astronomical basis for this count has been proved, and it may be that the 260-day count is based on the human gestation period. This is reinforced by the use of the tzolkʼin to record dates of birth, and provide corresponding prophecy. The 260-day cycle repeated a series of 20-day-names, with a number from 1 to 13 prefixed to indicated where in the cycle a particular day occurred.
  
  The 365-day haab was produced by a cycle of eighteen named 20-day winal s, completed by the addition of a 5-day period called the wayeb. The wayeb was considered to be a dangerous time, when the barriers between the mortal and supernatural realms were broken, allowing malignant deities to cross over and interfere in human concerns. In a similar way to the tzʼolkin, the named winal would be prefixed by a number (from 0 to 19), in the case of the shorter wayeb period, the prefix numbers ran 0 to 4. Since each day in the tzʼolkin had a name and number (e.g. 8 Ajaw), this would interlock with the haab, producing an additional number and name, to give any day a more complete designation, for example 8 Ajaw 13 Keh. Such a day name could only recur once every 52 years, and this period is referred to by Mayanists as the Calendar Round. In most Mesoamerican cultures, the Calendar Round was the largest unit for measuring time.
  
  As with any non-repeating calendar, the Maya measured time from a fixed start point. The Maya set the beginning of their calendar as the end of a previous cycle of bakʼtun s, equivalent to a day in 3114 BC. This was believed by the Maya to be the day of the creation of the world in its current form. The Maya used the Long Count Calendar to fix any given day of the Calendar Round within their current great Piktun cycle consisting of either 20 bakʼtun s. There was some variation in the calendar, specifically texts in Palenque demonstrate that the piktun cycle that ended in 3114 BC had only 13 bakʼtun s, but others used a cycle of 13 + 20 bakʼtun in the current piktun. Additionally, there may have been some regional variation in how these exceptional cycles were managed.
  
  A full long count date consisted of an introductory glyph followed by five glyphs counting off the number of bakʼtun s, katʼun s, tun s, winal s, and kʼin s since the start of the current creation. This would be followed by the tzʼolkin portion of the Calendar Round date, and after a number of intervening glyphs, the Long Count date would end with the Haab portion of the Calendar Round date.