【More・・・】
At what time was the schedule created?
In which period did the calendar initially devised?
In what period did the calendar emerge?
In which period was the agenda firstly invented?
In which period was the agenda originally conceived?
In which period did the calendar
initially established?
During what period did the schedule inception?
In what period was the timetable come about for the
first time?
Exploring the history and evolution of Advent calendars NPR