Concubines are women engaged in an interpersonal relationship with a man without being married to him, or at least not to the fullest extent of marriage, such that their position is inferior to that of a primary lover. The relationship often involves cohabitation and sexual activity. In polygamous societies, they may be legally married but bear a lower rank than that of the main wife.
By the time of the Ming dynasty, concubinage was a millennia-old tradition, and the consorts of the emperor were governed by a standardized ranking system. Under Ming system, immediately below the empress were the Imperial Noble Consorts, followed by the Noble Consorts, Consorts, and Imperial Concubines. As was the custom at the time, their feet and breasts were often bound to conform with popular conceptions of beauty, though concubines prized for their dancing such as Shao Jun were spared from this practice.
The Zhengde Emperor regarded his concubine Shao Jun highly among others and would use her cat-like skills to spy upon court eunuchs and ministers. Along with her best friend Zhang, the pair rose to the rank of Imperial Concubine and were poised with the position of Imperial Consort. Because of her talents, the Zhengde Emperor took Shao Jun with him in his expeditions against Mongols to serve as his spy. After the Zhengde Emperor's death and with the royal court in disarray, Shao Jun joined the Assassin Brotherhood while Zhang decided to stay in the palace as a concubine. When Zhu Houcong was placed on the throne by the Templar eunuchs, becoming the Jiajing Emperor, Zhang rose to the position of an Empress and became the Emperor's second wife.
In 1530, the Templars Zhang Yong and Qiu Ju exploited Empress Zhang's friendship Shao Jun to lure the Assassin back to the Forbidden City, forcing her to deliver a message requesting a meeting. In the meantime, they threatened to kill several concubines they found disobedient. However, their plot was foiled as Jun rescued those concubine and killed Qiu Ju in personal combat, causing Zhang Yong to flee.
In China, it was common practice for prestigious men to have several concubines. For that reason, the Emperor of China usually had thousands of concubines, each who were ranked according to a strict hierarchy. As ladies of the court, the concubines were taught the finer arts of music, dance, singing, literature, and embroidery. The highest of the consorts was the empress, and only she held the official status of wife to the emperor.
Only heirs of the empress had the right to be designated crown prince. Despite her prestigious position, concubines of lower rank could potentially climb the hierarchy and succeed her, in which event, she was deposed. Even the most influential concubines paled before the power of the emperor, who had the authority to order their executions on a whim.