Five Hegemons
Duke Xiao's father was Duke Huan of Qi, who was the first of the Five Hegemons, the most powerful rulers of the Spring and Autumn period. Duke Huan had at least three main wives who bore no sons, six favoured concubines, and more than ten sons. Duke Xiao was then known as Crown Prince Zhao, and his mother was Zheng Ji, a princess of the State of Zheng. Five other sons of Duke Huan also contended for the throne: Prince Wukui, Prince Pan (later Duke Zhao), Prince Shangren (later Duke Yi), Prince Yuan (later Duke Hui), and Prince Yong.