Longpingji 隆平集 "Magnificient Pacification" is a history of the early Northern Song period 宋 (960-1279) that was attributed to the Song period writer Zeng Gong 曾鞏 (1019-1083). Yet in his various biographies or his funeral praise (xingzhuang 行狀) the Longpingji is not mentioned. In 1081, Zeng served as editor in the Historiography Institute (guoshiguan xiuzhuan 國史館修撰). It is known that he submitted an imperial biography called Taizu zonglun 太祖總論 at that time, dedicated to the founder of the Song dynasty, but the present emperor was not content with the text and dismissed him from the historiography institute. He had only worked there for five months and might barely had the occasion to do sufficient research in the archives to compile the Longpingji.
The author must therefore have been an anonymous person who used Zeng Gong's famous name for marketing purposes. The 20-juan long book describes the reigns of the first five emperors of the Song dynasty. It is divided into 26 chapters and imitates the structure of the official huiyao 會要 collections on statecraft (see Tang huiyao 唐會要), which means that the whole book is not written as a chronicle but treats the history of various state offices and institutions during that time. The text is very concise, but it was very widespread in the late Northern Song period and served for the compilation of the official dynastic history Songshi 宋史.