During what period did the timetable invented?
In which period did the calendar first devised?
During what period was the schedule emerge?
During what period was the agenda initially devised?
During what period did the schedule initially envisioned?
In which period was the timetable initially established?
In what period was the agenda inception?
At what time did the agenda emerge for the first time?
Mesoamericans Have Been Using a 260Day Ceremonial Calendar
