The Mesoamerican Calendar article
In which period did the schedule created?
In what period was the timetable initially devised?
In which period was the timetable emerge?
During what period did the timetable originally devised?
In which period did the timetable firstly conceived?
In what period did the timetable initially created?
In what period did the schedule inception?
During
what period was the agenda arise for the first time?
