Keeping time The origin of BC and AD During what period was the agenda invented?
In what period was the agenda first introduced?
During what period did the calendar come into existence?
During what period did the timetable firstly invented?
During what period was the calendar originally envisioned?
In which period was the timetable firstly introduced?
In what period was the schedule inception?
When was the timetable come about for the first time?
