This study examines traditional ideas of women and marriage, based on the instructions attributed to one of the rulers of the epoch of the “Religious Kings”—Usun-Debeskertu-Khan, and his ministers. The focus is made on female virtues, the most important of which is adherence to duties in relation to the husband and children. The standards that noble women had to comply with were higher than those concerning other women, but still quite realistic, as attested to by historical records. Negative female traits were said to be caused by untamed emotions, which cause one to forget about commonly accepted norms of behavior. The analysis of the instructions relating to marriage suggests that they were especially influenced by Buddhism, which, using various forms of instruction, including didactic writings, endowed marriage with a new, spiritual content. There were three forms of marriage, tentatively described as “divine”, “earthly”, and “infernal”. The causes of happy and unhappy marital unions were believed to be mainly related to women’s properties mentioned in the instructions. Marital harmony was said to depend mostly on the woman.