In which period did the calendar created?
During what period was the agenda initially devised?
In which period was the agenda emerge?
In what period did the calendar initially invented?
In which period was the schedule firstly imagined?
In what period did the timetable firstly established?
At what time was the schedule creation?
At what time was the calendar arise for the first time?
The History of Calendars and How They Evolved Calendar
