The Mayan Calendar
The calendar of this ancient civilization is of interest now simply because it was thought that it prophesied the end of the world in 2012; instead it marks the end of an age and also the begin of a new one. On the day of the winter solstice in 2012, which will fall around December 21, their fantastic circle of time calculation, which began in what we refer to as 3114 B.C.E., will end - and also the next one will begin.
It's the most complex of all calendars, with four separate calendars operating at once, which could be synchronized and interlocked in complex methods, their combinations giving rise to further, more extensive cycles.
The Tzolkin is really a sacred Mayan religious calendar based on a cycle that repeats each and every 260 days. It combines with the Haab, the typical, roughly seasonal calendar that consists of 18 months of 20 days every, followed by a short month of five days. Although the latter calendar is 365 days in length, the Mayans never utilized it on its own to determine the length of the year, instead combining the two. Every cycle of Tzolkin and Haab repeated itself each and every 52 Haab years more than the life expectancy of most individuals so this was deemed sufficient.
Another form of calendar, known as the Long Count, was utilized to track longer periods of time, and for identifying when one event occurred in relation to others. A 584-day Venus cycle was also maintained, which reflected the appearance and conjunctions of the planet Venus and was utilized to determine when to go to war.