Du You
The first classic work about the Tang is the "Old Book of Tang" by Liu Xu (887–946) et al. of the Later Jin, who redacted it during the last years of his life. This was edited into another history (labeled the "New Book of Tang") in order to distinguish it, which was a work by the Song historians Ouyang Xiu (1007–1072), Song Qi (998–1061), et al. of the Song dynasty (between the years 1044 and 1060). Both of them were based upon earlier annals, yet those are now lost. Both of them also rank among the "Twenty-Four Histories" of China. One of the surviving sources of the "Old Book of Tang", primarily covering up to 756, is the "Tongdian", which Du You presented to the emperor in 801. The Tang period was again placed into the enormous universal history text of the "Zizhi Tongjian", edited, compiled, and completed in 1084 by a team of scholars under the Song dynasty Chancellor Sima Guang (1019–1086). This historical text, written with three million Chinese characters in 294 volumes, covered the history of China from the beginning of the Warring States (403 BC) until the beginning of the Song dynasty (960).