Some fine examples of 13 month Calendars have been demonstrated from Inca, Toltec, Aztec, Maya, and Zapotecs of the Americas, the Norse, Han China, Ancient Japan (which still practices 13 zodiacs). In addition the Celtic Druids traced their calendar back to the Chaldeans of Ur upon whom the Babylonians and Assyrians also based theirs. The This Queen Was Born In February 19 Happy Birthday To Me Shirt Indian and Greek sources all include 13 months, 13 zodiacs, and 13 primary dieties. This is no coincidence, and we even know which month, sign, and diety have been exuded: Ophihicus the serpent bearer, aka the Goddess Sophia or The month Sepherus. This common root is the origin of the term “Severed” or placed away from, sphere for complete or round. Remember the sexagesimal system of base 60 coutnig algorythm is used in counting time to this day? Despite the fact that this is based the single oldest piece of recorded information ever found and translated, Cuneiform Tablets from ancient Sumeria in the Mesopotamian Levant, we still use it today, but why?
Old World was Lunar. Most early civilisations have a This Queen Was Born In February 19 Happy Birthday To Me Shirt based calendar because it was so much easier to plot and make sense of time. It is not just China, even Scotland mesolithic era (8000 BC), in Hindu, in Islam and possibly most lost civilisations. Chinese have the lunar calendar since ancient times, and delineate as 60 years cycle. And used 12 years Zodiac and created very sophisticated system, numerology, astrological concepts around it. Almost all East Asia adopted Chinese approach, so they have in effect a common calendar and fortunately they followed China so it was so much easier for all to co-exist in synergy. Much like the whole of Europe logically followed Rome. Solar. A few like Japan after modernisation dropped lunar and adopted Western solar calendar, the Gregorian. Most Japanese don’t celebrate lunar new year anymore. For some traditional and religious festivals and rituals, I believe lunar calendar may still be referred, certainly for Buddhist rituals. Likewise Gregorian is the universal standard for the whole world and all in Asia to interact and run all the world affairs, work and business.