From Don? Bai Juyi? Song of everlasting regret Ancient poetry network query, pear flower with rain from the Tang Dynasty? Bai Juyi? Eternal sad song: tears fall down her sad white face, like spring rain on pear flowers. Song of Eternal Sorrow is a long narrative poem by Bai Juyi, a poet in the Tang Dynasty. The whole poem vividly describes the love tragedy between Xuanzong of Tang Dynasty and Yang Guifei. The poet created a touching story with historical figures and legends.