In what period was the timetable created?
When was the timetable first introduced?
In what period was the timetable arise?
In what period did the timetable firstly invented?
In
which period did the calendar firstly thought up?
At what time was the timetable firstly devised?
During what period was the timetable generation?
In which period did the calendar arise for the first time?
Advent calendar Wikipedia
