The Essentials of the Military Arts (Wujing zongyao) was completed in the early Song (1043) by Zeng Gongliang, Ding Du, and others at the order of Emperor Renzong. The book has four parts, including institutions, frontier defense, campaign anecdotes, and divination. The book can be seen as an encyclopaedia of Chinese military arts till the Song time. Its topics range from military strategy and organization, to infantry and cavalry training, the production and employment of weapons, and famous campaigns of earlier periods. The large number of illustrations in the book make it especially valuable as a source for the military technology of the time.