What do Du Mu and Liu Zongyuan collectively refer to?

Du Mu and Liu Zongyuan are both figures in the Tang Dynasty, with high literary accomplishment and works, which are worth learning by many people. If the two are called together, it should be called "Liu Du", which is also the title of future generations.

Du Mu (803-852), a native of Mu Zhi, Fan Chuan, was a scholar of Jingzhao Wannian (now Xi, Shaanxi). Famous poets and ancient writers in the late Tang Dynasty. He is good at five-character ancient poems and seven laws. He used to be the Sheren of Zhongshu (alias province of Zhongshu), known as Du. His poems are handsome, brilliant and full of practical things. They achieved great success in the late Tang Dynasty, and the world called them (Xiao Du) to distinguish them from Du Fu. Li Shangyin is equally famous (Little Du Li). His representative works include Four Wonders, Tomb-Sweeping Day, Jiangnan Spring, etc.

Liu Zongyuan (A.D. 773- A.D. 8 19), a native of Hedong (now Ruicheng and Yuncheng, Shanxi), was one of the eight masters in Tang and Song Dynasties. He was a writer, philosopher, essayist and thinker in the Tang Dynasty. He was known as "Liu Hedong" and "Mr. Hedong" in the world, and was also known as "Liu Liuzhou" because of his official residence in Liuzhou. Liu Zongyuan and Han Yu are called Liu Han, Liu Yuxi is called Liu Liu, and Wang Wei, Meng Haoran and Wei Wuying are called Wang Meng. Liu Zongyuan left more than 600 poems in his life, and his achievements in writing were greater than poems. Nearly a hundred parallel essays, argumentative essays, sharp and ironic. There are many places where scenery is described in travel notes, such as The Collection of Mr. Hedong, with representative works such as Xiju, Jiang Xue and Fisherman.