Bai Juyi's "Song of Eternal Sorrow" belongs to the narrative poem of seven-character ancient poems (relative to the modern style), also known as "Gexing" style. It is not a metrical poem, and its metrical style is more free than modern poetry. This kind of poem is longer than the narrative and easier to understand. The most famous ones are Bai Juyi's Song of Eternal Sorrow on Pipa and Yuan Zhen's Poems of Lotus Palace, which are also called Changqing Style because they were popular in the Changqing period of the Tang Dynasty.