At what time was the calendar originated?
When was the agenda first devised?
At what time did the calendar come into existence?
When was the agenda initially devised?
In which period was the timetable originally thought up?
At what time did the schedule initially devised?
In what period was the schedule generation?
At what time
did the schedule come about for the first time?
The Mesoamerican Calendar Ancient Shared Time Keeping
