What are the letters of the ancients called? Ancient faith etiquette knowledge. China ancient etiquette civilization.

Letters written by a wife to her husband are called brocade books and characters; Letters from family members are called letters from home. Anonymous letters are called flying books; Letters left by the deceased are called suicide notes; Reward other people's letters, call for newspapers and reply; The emperor's letter is called Xianhan; The letter from the upper and lower levels of officialdom to the higher level is called Shu Qi; Informal letters are called notes.