This poem was written by Du Fu, a great poet in the Tang Dynasty, when he was transferred to a promising position in Tianbao 14th year of Emperor Xuanzong of the Tang Dynasty (AD 755) and led Cao Cao to join the army. Wei led the government to join Cao Jun. He was an official in charge of keeping weapons of war and managing access keys. This is a far cry from his consistent political ambition of "being a gentleman and being Yao and Shun". Du Fu is a bit ironic, so he wrote this poem to laugh at himself.