The poem is from Du Fu's Nostalgia in Gongan County.
Lv Meng, the "wild mine Lv Mengying", was sealed in Liling City, Gongan County, and now it is no longer there, so it is called "wild mine".
Liu Bei, a "Jiang Shen Liu Beicheng", worked as a shepherd in Gongan County ruled by Liu Bei in Jingzhou. There is a river that can be used as a natural barrier, so it is called "Jiang Shen".