"Book of Jin" is one of the "Twenty-Four Histories" of China. It was compiled by more than 20 historians including Fang Xuanling and Chu Suiliang of the Tang Dynasty in the 20th year of Zhenguan (646). It took more than two years to complete the book. The whole book originally consisted of 132 volumes (including one volume each of narrative and table of contents), but some of them were later lost. The existing 130 volumes are divided into ten volumes of imperial chronicles, twenty volumes of chronicles, seventy volumes of biographies and thirty volumes of records. It records the history from Sima Yi of the Three Kingdoms to the fall of the Eastern Jin Dynasty (420 years), and pioneered the "records" style to record the sixteen-state regime established by the Xiongnu, Xianbei and other ethnic minorities. This book describes the stories and historical events in vernacular Chinese.
Why is it not vernacular anymore?