The Western calendar of 12 months is also influenced by the path of Christ and the 12 stations of the Cross which form a part of Catholicism and the calendar was, in fact, created by Pope Gregory XIII who replaced, across Christendom, the Julian calendar introduced by Roman Emperor Julius several decades B.C.
We might imagine that the western calendar is ancient but it dates back only to the early 16th Century. One of the effects was to standardise the year: for example, the English New Year began on the Spring Quarter Day, known as Lady Day and the start of the festivities that included May Day and a very different kind of pole dancing to that we think of today. In Germany, states set their own calendars.
The Julian calendar did not take into account the differences between tropical and polar suns and, although it did recognised that a year was not exactly 325 days, its calculation was a little (but not by much) crude. As a result, there were discrepancies and the drift had reached the point where, by Gregorian times, there were differences of 11 days. “at the first council of Nicaea, in 325, it was decided that Easter should be celebrated on the first Sunday following the full moon occurring after the vernal equinox of 21 March. Therefore, it could not be before 22 March and after 25 April. In 1582, the vernal equinox was on 11 March of the Julian calendar, whereas it should have been on 21 March.”* So the Pope fixed it. It caused temporary chaos as calenders all over the Christian world were reset. And it relates to the sun.
The Western zodiac relates to the relative positions of the stars. It’s obvious to us today that the heavens are a three-dimensional space. Some stars, and some constellations, are closer to earth than others. The fact that heavenly bodies could move across the sky, up, down, left, right, while some groups kept their shape and others roamed, seemingly, free fascinated people. So they looked at groups of stars that kept their shapes and gave them names. The names they gave were based on crude join-the-dots pictures and once they had something they thought was broadly identifiable, the used the names and they stuck. So, there you have it – age-old astronomers were early influencers. The stars have much more in common with the sun (they are, after all, themselves suns) than with the moon. And so, we ended up with 12 signs of the annual zodiac which don’t relate to either the Gregorian calendar nor, it seems, to the Julian.
December 22 is actually the Winter Solstice. December 25 is an old Pagan festival date. Although there are opinions, no one seems to know why 1 January should fall a week later to be the start of a new calendar year.