Much of Liao literature was lost,but judging from what we have today,we can see the general style and features of Liao prose were roughly the same as those of Five Dynasties and Song Dynasty,though its poetry was comparatively course.The Jin literary works are mostly poems and essays,and its early writers came from Song Dynasty.After Dading Era under the reign of Emperor Shizong,literary creation began to flourish and such celebrated writers as Yuan Haowen and Wang Ruoxu are produced.Different from Liao and Jin who were only regional powers,Yuan Dynasty was a unitary kingdom established by Mongols.As a result,the Yuan literature was prosperous in all genres,especially its opera Za Ju,which laid the foundation of traditional Chinese performing art,occupied a key position in Chinese literary history and produced such important playwrights as Guan Hanqing,Wang Shifu and Ma Zhiyuan.Nan Xi(Southern Opera),which appeared during Song Dynasty,also continued to develop rather than fell out of fashion,with Pi Pa Ji as its representative.The flourishing of San Qu(desultory song) was another important sign of the development of poems with irregular lines after that of Ci in Song Dynasty.The Yuan poems with regular lines continued the writing tendencies of modeling after Tang poetry in the late of Song and Jin Dynasties and exerted influence on Ming and Qing poems.