Sun Yi was the third son of the warlord Sun Jian and his wife Lady Wu. He was known for his martial valour and fiery personality, which made him resemble his eldest brother Sun Ce. He was nominated as a "xiaolian" (civil service candidate) by Zhu Zhi and served in the office of the Minister of Works. After Sun Jian was killed in action at the Battle of Xiangyang in 191, Sun Ce succeeded him and took over command of his troops. Between 194 and 199, Sun Ce launched a series of conquests in the Jiangdong region and established his power base there. In 200 CE, when Sun Ce was mortally wounded during a hunting expedition, his adviser Zhang Zhao and other subjects believed that he would designate Sun Yi as his successor, but Sun Ce chose his second brother Sun Quan instead.