A number of kings from Chinese history appeared as characters in Jin Yong's stories. Among these, the two rulers in DGSD (King Deun Jing Ming of the Dali Kingdom and King Yeh Lut Hung Gei of the Khitan Liao Kingdom) were depicted as significantly better men in the stories than their real-life counterparts supposedly were in history. In DGSD, King Deun Jing Ming appeared to be the ideal ruler: he was strong, ethical, wise, compassionate, humble, and always had the best interests of his people in mind. Similarly, DGSD depicted King Yeh Lut Hung Gei as an honorable man and a good ruler.
From what I read about the historical Deun Jing Ming and Yeh Lut Hung Gei, however, neither king was nearly as good as Jin Yong depicted them.