She was the daughter of Emperor Gaozong and Empress Wu Zetian . `` Princess of Peace '' , personal name unknown ) ( died 2 August 713 ) was a princess of the Chinese dynasty Tang Dynasty and her mother Wu Zetian 's Zhou Dynasty . She was the youngest daughter of Wu Zetian and Emperor Gaozong and was powerful during the reigns of her mother and her elder brothers Emperor Zhongzong and Emperor Ruizong ( both of whom reigned twice ) , particularly during Emperor Ruizong 's second reign .