《宋史·本纪·卷十》
秋七月十二日，派遣使臣告诉契丹，宋朝出兵攻讨元昊。十七日，检阅各军练习作战。
秋七月乙丑，遣使以讨元昊告契丹。庚午，阅诸军习战。
On the 12th day of the seventh month of autumn, an envoy was sent to tell the Khitan that the Song Dynasty had sent troops to attack Yuan Hao. On the 17th, the armies were inspected in combat practice.