Bai Juyi's long narrative poem that was as famous as the pipa song was the Song of Everlasting Regret. Song of Everlasting Sorrow was a narrative poem that described the court struggle of the Tang Dynasty and the love story between Emperor Xuanzong and Yang Guifei. It was regarded as one of the representative works of the Tang Dynasty's narrative poems and a classic in the history of Chinese literature. The poem was based on the story of Emperor Xuanzong of the Tang Dynasty and Concubine Yang. It described the political struggle and the distortion of human nature in the court of the Tang Dynasty by describing the debauchery of Emperor Xuanzong of the Tang Dynasty and the grief of Concubine Yang. Song of Everlasting Sorrow used a wealth of rhetorical devices such as metaphor, contrast, and parallel. It was praised as one of the representative works of narrative poetry in the Tang Dynasty.