Wu Zetian was only one woman emperor of ancient Central Nation. She was born in A.D. 624 in Bing Zhou where was in modern-days Shanxi Province. At the age of 14, she was selected to be a Cairen which was a title of a lower concubine in the period of Tang Tai-Zong who was the second emperor. After the death of Tai-Zong, she became a Buddhist nun according to court rituals. One day Tang Gao-Zong, the son of Tai-Zong, met her in the temple and became enamored of her beauty. So he recalled Wu Zetian and let her be a Zhaoyi. This title was higher than Cairen.