2. During the period of Emperor Wu of the Han Dynasty, Yuefu official office was formally established, with Li Yannian, who was proficient in music, as the captain of the association, responsible for making music scores and training musicians, and collecting folk songs on a large scale. With the establishment of Yuefu official office, the folk songs of the Han Dynasty were preserved in large quantities, and when the literati poetry circle of the Han Dynasty was particularly neglected, they shone brilliantly, forming the third important development stage in the history of China's poetry after The Book of Songs and Songs of the South.
3. Han Yuefu folk songs have a wide range of themes and rich contents. Some of these poems exposed the extravagance and cruelty of bureaucrats and nobles, reflected the pain of working people's lives, showed the sharp class opposition in Han society, and conveyed the angry and rebellious voice of the oppressed people.