In which period was the agenda invented?
At what time did the schedule initially introduced?
During what period was the timetable come into existence?
In which period did the agenda originally devised?
During what period did the schedule originally thought up?
In what period was the schedule firstly devised?
In which period did the agenda creation?
When did the timetable emerge for the first time?
Mesoamerican Calendars and Archaeoastronomy