In what period did the schedule created?
During what period did the calendar initially introduced?
At what time did the agenda arise?
In which period was the agenda originally invented?
During what period did the timetable originally conceived?
When did the schedule firstly created?
At what time did the schedule creation?
At what time did the calendar come about for the first time?
- 04/13/01:39
- Exploring the history and evolution of Advent calendars NPR
