The Yiyuan ape-man fossil, discovered to the east of Mt. Tai, proves that the region was inhabited by the ancestors of human beings five hundred thousand years ago. A girl's molars discovered at Wuzhutai of Xintai shows that the inhabitants there had bid farewell to the paleobithic period and entered the thinking man period. By 5000 years B.C. this region was in the thriving period of Dawenkou Culture which reflects the process of transiton of matriarchal society to patriarchal society and the disintegration of primitive society.