《明史·志·卷六十五》
每年征调中都、山东、河南、大宁的军队轮番到京城守卫，隶属京军。
岁调中都、山东、河南、大宁兵番上京师隶之。
Every year, troops from the Zhongdu area, Shandong, Henan and Daining were drafted to take turns at guarding the capital and belonged to the metropolitan army.