Evidence for this is September October November and December are named as seventh eighth ninth and tenth months which matches with a year starting in March obvi

Evidence for this is September October November and December are named as seventh eighth ninth and tenth months which matches with a year starting in March obviously intentionally at the spring equinox but calendar inaccuracies lost that. Quarters should begin and end with equinoxes and solstices and be equivalent with seasons, major holidays aligned with quarter transitions and solar milestones make sense.