Is there a reason why the middle of the month is called Idus? the First of the month Kalendae and the ninth day before the ides is called nonae? I can’t figure it out? Why not just call the first day of the month primus etc? Were these originally some sort of religious feast day and if so what were their sigificance and what gods were worshiped.
Sorn
I believe the theory goes something like this:
The Roman calendar was originally a lunar calendar. The Kalends was the day of the new moon, the Nones was the day of the half moon, and the Ides was the day of the full moon. Eventually the dates were fixed rather than being based on readings of the moon.
The days did have importance that made them notable. Interest was due on the Kalends, and the Ides was considered very auspicious. Of course, anyone could also just look at the night sky to get an idea of what the date was.
I know having the days of the month counted 1-31 makes sense to us because that’s what we’re used to. But there’s no reason a priori to do it that way.