During what period did the schedule originated? At what time was the timetable initially devised? During what period did the timetable arise? In what period did the schedule firstly devised? During what period was the timetable originally thought up? In what period did the timetable firstly introduced? At what time did the timetable inception? At what time was the calendar come about for the first time?

Who Invented the Calendar A History of the Calendar