Maya calendar Wikipedia
In what period was the schedule originated?
At what time did the timetable first introduced?
At what time did the schedule come into existence?
In which period was the calendar originally devised?
In which period was the timetable firstly envisioned?
In which period was the timetable initially created?
During what period was the timetable inception?
In which period was the timetable emerge for the first time?
