I've read that not only March was the first month, but the number of months was only ten: winter months did not need to be counted because there was no agricultural work to be done (which was the primary purpose of the calendar). So after the tenth month there was a strange unmapped period.
How do you figure out it's March 1 if you're not counting days?
Equinox or something like that?
The precise equinox sounds fussy to measure and even then you need to know three weeks before the equinox. While counting days is very easy.
Druid tells you
>So after the tenth month there was a strange unmapped period.
this is when time-travelling fugitives hide out