The Han dynasty is associated with the early recorded use of the 12-animal Chinese zodiac cycle.
The Chinese zodiac connects the 12 earthly branches with a repeating sequence of animals. Historical evidence places the system’s documented development in the Han period, which lasted from 202 BCE to 220 CE. The animals may have older cultural roots, but the precise origin story remains uncertain.
The zodiac was not created as a single modern-style invention. It grew from calendrical and astrological traditions involving the earthly branches, which were already used to organize time. Animal names were later attached to those branches and became widely familiar across East Asia.
Popular stories, including the famous animal race, explain the order symbolically rather than proving when the system began. The Han association therefore refers to early written and calendrical evidence, not necessarily the moment when every animal tradition first appeared.