《宋史·本纪·卷二十二》
冬十月初五，改燕京为燕山府，琢、易八州都赐给名称。
冬十月庚寅，改燕京为燕山府，涿、易八州并赐名。
On the 29th of the tenth lunar month, Yanjing was renamed Yanshan Prefecture, and the eight states of Zhuozhou and Yizhou were given new names.