The records of the first Chinese new year celebration can be traced to the Warring States period (475 BC – 221 AD). In the "Lüshi Chunqiu", in Qin state an exorcism ritual to expel illness, called "Big Nuo" (大儺), was recorded as being carried out on the last day of the year. Later, Qin unified China, and the Qin dynasty was founded; and the ritual spread. It evolved into the practice of cleaning one's house thoroughly in the days preceding Chinese New Year.