We had a discussion regarding the 366 degree circle and such a while back, but I can't find the thread. So I will start again ... sorry!
First of all let's look at a few bits of maths and then add some superstition and facts to that and see if I make sense.
OK I believe the earliest 'year' was not 366 days nor could the circle have had 366 degrees. This kinda goes against established theories such as the megalithic yard. It certainly buggers up the actual length stated by Thom.
We know we have 28 days in a lunar cycle. Women's periods follow (in most cases) this same cycle. This is probably where the Mother Goddess comes from and gets associated with the moon. Also there are three stages to the moon 1=WANE, 2=FULL, 3=WAX. These are known to be similies for youth, maturity and old age of the Triple Goddess.
28 * 13 = 364 ! So if we have 364 days in our year we can have 13 equal months that we can associate with lunar cycles. The winter solstice (the last day of the year?) always falls in the 13 month. Is this why 13 is unlucky? When the sun dies.
Let's look to pre-Hellenic Greece mythology. The nymph (Goddess?) spirit always took a new king every four years. To make this choice there was an extra day added to the year and games were held to choose a champion for sacrifice. Is this the roots of the olympic games?
So, in later times, by altering the year and the month it was no longer in synchronisation with the woman. It could no longer give rise to power for the Matriarch as she was no longer in control of the year.
This could all be a pile of rubbish of course. Am I tying in facts that do not belong together? I don't think so, maybe you do though.