《魏书·列传·卷十二》
于是迁移青州齐州和道固一起守卫城池的名门望族几百家到桑干，在平城西北的北新城建立平齐郡。
乃徙青齐士望共道固守城者数百家于桑乾，立平齐郡于平城西北北新城。
As a result, hundreds of highly respected families from Qingzhou, Qizhou, and Dao Gu were relocated to Sanggan, where they were ordered to guard the city. A new city was constructed northwest of Pingcheng and named Pingqi County.