Why are there twelve constellations?

More than 2000 years ago, the Greek astronomer Hipparchus (190 ~ 120 BC) divided the ecliptic into twelve segments, with spring divided into zero, and every 30 degrees from the vernal equinox (that is, the zero degree of the ecliptic) as a palace, taking the main constellations contained in each palace at that time. Babies born when the earth moves to every bisector (constellation) will always have some similar characteristics when they grow up, including behavioral characteristics and personality characteristics. Connect these associations (rich imagination and creativity) in series to make the humanity of these constellations concrete; It also adds the color of myth and becomes an important part of culture (mainly Greek and Roman mythology).