Duke Zhao'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 Zhao was then known as Prince Pan, and his mother was Ge Ying, a princess of the minor state of Ge (葛). Five other sons of Duke Huan also contended for the throne: Prince
Wukui, Crown Prince Zhao (later
Duke Xiao), Prince Shangren (later
Duke Yi), Prince Yuan (later
Duke Hui), and Prince Yong. When
Duke Huan died in the tenth month of 643 BC, the six princes
fought one another for the throne.
Wukui prevailed at first, but he sat on the throne for only three months before being killed by supporters of Crown Prince Zhao. Prince Zhao ascended the throne with the help of
Duke Xiang of Song and was known as
Duke Xiao of Qi. Duke Xiao reigned for ten years. After he died in 633 BC, Prince Kaifang of
Wey, who had been a trusted official of Duke Huan, killed Duke Xiao's son and helped Prince Pan usurp the throne. Prince Pan is posthumously known as Duke Zhao of Qi. ==Reign and succession==