Wang Mang
Wang Mang promised at the time that he would return the throne to Emperor Ruzi as soon as he was old enough, but in 8 AD, Wang Mang seized the throne and established the Xin Dynasty. In 9 AD, the toddler Emperor Ruzi was created the Duke of Ding'an (定安公), and Empress Dowager Wang was given the title of Duchess Dowager of Ding'an.