When was the timetable originated?
In which period did the calendar initially devised?
During what period did the schedule come into existence?
In which period was the timetable firstly invented?
In which period was the timetable firstly envisioned?
When did the schedule initially introduced?
In which period was the agenda generation?
At what time did the agenda arise for the first time?
Counting down to Christmas A history of the Advent Calendar
