As time passed and the ancient Maya civilization declined, the Long Count became less used in its full form. Instead a shorter form known as Period-Ending began to be used.
The ancient Maya used the Period-Ending version of the Long Count at least since around the Late Classic period. Period-ending dates counted katuns and the day the katuns ended on. Period-ending dates still used both calendars of the Calendar Round. The period-ending dates form a cycle that does not repeat for around 19,000 years.
An example of the period-ending date format goes like this. If it was the 8th katun and it ended on 4 Ahau 13 Cumku, then it would be written katun 8 4 Ahau 13 Cumku.
The Period-Ending version was itself eventually replaced by an even shorter version of counting katuns. This second version is called the Short Count.
“The Ancient Maya”; Robert J. Sharer, Loa P. Traxler; 2006