《资治通鉴·魏纪·魏纪四》
汉后主命右中郎将宗预出使吴国，吴王问道： 吴国与西蜀，尤如一家，可是听说西蜀却增加了白帝城的守军，为什么？ 
汉主使右中郎将宗预使吴，吴主问曰： 东之与西，譬犹一家，而闻西更增白帝之守，何也？ 
The emperor of Shu sent the Right Middle General Zong Yu to Wu as an envoy. The king of Wu asked him, “Wu and Xi Shu are like one family, but I hear that you have increased your forces at Baidicheng. Why is this?” 