Why is Pisces first?

[Koen G]

For thread restoration's sake, I wrote here before that during the first centuries BCE the Roman calendar corresponded to the months as we see them now in the VM, December being the tenth (decem) and final month. Helmut then added that a number of European calendars, including the Venetian one, also used to start on March 1. Apparently the general conversion to January 1 only came during the 16th century.

So if we assume that the intention behind the series was to use it as some kind of calendar (somebody wrote month names on it after all), and we change the question to "why is March first?", then the answer should be clear: because some calendars started with March.