The first dated Chinese New Year's Eve was recorded during Warring States period (475 BC – 221 AD). In "Lüshi Chunqiu", an exorcistic ritual called "Big Nuo" (大傩) was recorded being carried out in the ending day of a year to expel illness in Qin (state). It was derived from an earlier ritual, Nuo (傩), which if the origin of Chinese New Year's Eve. Later, Qin unified China and founded the Qin dynasty, the ritual was continued. It evolved to cleaning up houses thoroughly in the preceding days of Chinese New Year.