The historical background reflected in Hou Ma's Joint Letter: the fierce and cruel struggle between the upper-class politicians in the late Jin Dynasty highlighted the historical role of "evil", reflected the historical trend of "ritual collapse and bad music" at that time, and thus reflected the difficult and tortuous course of the development of the Chinese nation.

The book of Hou Mameng is a jade cultural relic unearthed in Qincun 1965- 1966, houma city, China, with more than 5,000 pieces. Because the words on the jade plate contain the words recorded in the oaths between the vassal states or ministers during the Spring and Autumn Period and the Warring States Period, it is called "Oath Letter" or "Oath Letter". This kind of writing belongs to the official script of Jin State in the Spring and Autumn Period, which appeared in about 550 BC.

These characters written on jade articles are not only the earliest brush calligraphy found in China today, but also have artistic value because of their skillful and fluent strokes and vivid and changeable glyphs. The book of Houmameng is one of the top ten archaeological discoveries in China since 1949, and one of the top ten national treasures of Shaanxi Provincial Museum.

From the content of Hou Ma's League Book, we can also examine the ideological changes of his time. At the end of the Spring and Autumn Period, Confucius had clearly pointed out that the whole society was in turmoil, lacking in honesty and morality. It is precisely because of the moral decay that a large number of treacherous words and deeds have appeared, and people who are allied with each other need to be bound by swearing, so as to unite people and consolidate internal affairs.

Obviously, the disintegration of this moral concept is a reflection of great social turmoil and great changes. A large number of Hou Ma League letters are conclusive empirical materials for the drastic changes of this era.