Everyone is very happy. Who are Princess Sasha's parents?

In the TV series "Everyone is Happy", Princess Sasha's parents are the daughters of the prince (later emperor) and the duke, that is, the daughter of the emperor and the granddaughter of the duke. Princess Sasha is the emperor's niece, having an affair with the princes, and the plot is gorgeous. This TV series describes the life of a big family in the Ming and Qing Dynasties, emphasizing the importance of inheriting family culture and traditional values, and is loved by many viewers.