The Han, Wei and Six Dynasties were famous for Yuefu folk songs. Yuefu was originally a music institution established by Emperor Wu of the Han Dynasty, which was used to train musicians, make music scores and collect lyrics, among which a large number of folk songs were collected. Later, Yuefu became a poetic name with musicality. Fifty or sixty folk songs of Han Yuefu preserved today truly reflect the miserable life of the lower classes. For example, the battle of the south of the city, the trip to the East Gate, joining the army during the Tenth Five-Year Plan, and going to the countryside. Their stylistic schools, The Book of Songs and Songs of the South, are more lively and free. They develop five-character style, seven-character style and long and short sentences, mostly focusing on narration and shaping characters with certain personality. Peacock Flying Southeast (also known as Jiao Zhongqing's Wife) and Mulan Ci are outstanding representative works of Yuefu narrative folk songs since the Han and Wei Dynasties, which are called Yuefu Double Walls.