2012 - Science Or Superstition?/AM/4

From Organic Design wiki

The Long Count develops to a much greater degree in some sites, to lesser degree in others. Some sites will only utilise the 260-day count and most of their hieroglyphic inscriptions to not incorporate the long count. Other sites will develop more complex cycles, such as the 819-day cycle that Palenque developed. The calendar is manipulated and utilised in different sites to a different degree, but we can say that throughout the Mayan world that system was prevalent during the middle-to-late classic period, it being abandoned shortly after the decline and subsequent abandonment of some of these great sites.