These three pieces of calligraphy belong to the fifth century, the period generally know as the Five Barbarians and Sixteen Kingdoms (Wuhu Shiliuguo), when north China was divided into many different small kingdoms. Jianping is the reign name of Murong De, Emperor Xianwu of the Southern Yan (reigned 400-406). Xuanshi is the reign name of Zuqu Mengxun, Emperor Wuxuzn of the Northern Liang (reigned (401-433).
All three pieces are contractual agreements of this period. The calligraphic style of each piece compares very well with the piece, Li Bo Wenshu (Li Bo's calligraphic piece), also belonging to the same time span in the Former Liang (346), now housed in the museum of the Ryukoku University, Japan. In the same manner as the Li Bo piece, the present three pieces are very important in providing documentary evidence on the development of calligraphic styles in China. While the Li Bo piece provides evidence of calligraphy by a historical person, the present three dated pieces provide evidence for dating other pieces with similar style