How Did People Count Years Before BC and AD MediumDuring what period was the schedule originated?
During what period was the schedule first introduced?
At what time was the calendar arise?
In which period was the schedule firstly created?
In which period did the timetable originally envisioned?
During what period was the agenda initially created?
In what period was the agenda generation?
In what period was the timetable emerge for the first time?