Human beings concocted their concept of "time" by daily observing the natural phenomenon of the movement of celestial bodies, most obviously of the Sun, and have adapted their activities to this solar motion ever since.
Not escaping this impulse, the Maya immersed themselves in numerology, and come up with the Mayan calendar, one of the greatest contributions to universal culture.
Watching the movement of the sun every day, and perceiving the existence of an order in the firmament of which he was a part, the Maya intuited that he came from the Gods, whom he identified with the celestial bodies and the natural phenomena around him. Sensing a practical aspect to these observations, systems of calendars were devised that allowed a suitable adaptation of the heavenly order to their social system.
To have a calendar is a world-wide necessity and in this aspect the Maya has excelled: one small example is that our calendar, which is known as the Gregorian calendar, accumulates an error of one day every 4000 years, however the Mayan calendar accumulates one day every 5000 years.
When this all began cannot be known exactly, nevertheless, what can be verified is that several regions of Mesoamérica were especially involved in using the Mayan calendar..
The Mayan calendar, considered one of the most exact in the world, is noted for the accomplishment of using the vigesimal system of base twenty.
http://www.caribemexicano.com/eng/mayancalendar/