《北齐书·本纪·卷四》
在遣之前，从西河总秦戍修筑长城束到大海，前后所修筑的东西共三千余里，大致上十里一座堡垒，在要害的地方设置州镇，一共二十五处。
先是，自西河总秦戍筑长城东至于海，前后所筑东西凡三千余里，率十里一戍，其要害置州镇，凡二十五所。
Just before this expedition, the general in charge of the Western Wei's frontier at Xi He region built a section of the Great Wall extending east to the sea; in all, the sections built east and west measured rather more than 3,000 li, with a fort approximately every ten li and twenty-five commanderies in key areas.