Why are there twelve months in a year?

There are three lunisolar calendar reform proposals: One is the Hermetic Lunar Week Calendar which normally consists of 12 lunar months and a leap month every 3 or 2 years, and with a year that always starts near the vernal equinox. Another is The Simple Lunisolar Calendar whose year always begins between Gregorian December 3 and January 1. The Irvember Calendar has the same names for the months as the Gregorian Calendar and adds an extra month called Irvember. Each year starts nearest to the day 78 days before the vernal equinox and uses a very accurate rule of 4366 months per 353 year cycle (130 leap years per 353 year cycle).