In what period did the calendar originated?
In which period was the calendar first introduced?
During what period did the timetable emerge?
In which period did the calendar firstly created?
During what period was the agenda firstly envisioned?
When did the timetable initially established?
In what period did the agenda generation?
In which period
was the agenda emerge for the first time?
- 04/13/01:39
- The history of calendars
