Zodiac constellations can be traced even further back, to Bronze Age (First Babylonian dynasty) sources, including Gemini "The Twins", from MAŠ.TAB.BA.GAL.GAL "The Great Twins", and Cancer "The Crab", from AL.LUL "The Crayfish", among others. Around the end of the 5th century BC, Babylonian astronomers divided the ecliptic into twelve equal "signs", by analogy to twelve schematic months of thirty days each. Each sign contained thirty degrees of celestial longitude, thus creating the first known celestial coordinate system. Unlike modern astronomers, who place the beginning of the sign of Aries at the place of the Sun at the vernal equinox; Babylonian astronomers
Astrological sign operate on cycles of years, lunar months, and two-hour periods of the day (also known as "shichen"). A particular feature of the Chinese zodiac is its operation in a 60-year cycle in combination with the Five Phases of Chinese astrology (Wood, Fire, Metal, Water and Earth). Nevertheless, some researches say that there is an obvious relationship between the Chinese 12-year cycle and zodiac constellations: each year of the cycle corresponds to a certain disposal of Jupiter. For example, in the year of Snake Jupiter is in the Sign of Gemini, in the year of Horse Jupiter is in the Sign