Feng Dao served ten emperors successively. Why did the principle of "one minister does not serve two masters" fail?

In ancient times, the relationship between monarch and minister was very strict, and there was always a rule that one minister could not serve two masters, because under the ancient monarch thought, one minister had to serve a monarch all his life. If you die, you must not serve others. However, there was a prime minister who served ten emperors back and forth. He can be said to be a "tumbler" in troubled times. He is Feng Dao.

Feng Dao was born in the late Tang Dynasty. He was born in troubled times. When Feng Dao came of age, it was five generations, that is, you could not live in peace. Dynasties change frequently, and monarch change is even more common. In this social turmoil, Feng Dao served as Zhongshu and Sangong for nearly 30 years. His official career was not shaken by the torrent of troubled times, but smooth sailing.

Except for the five emperors, the foreign emperors of Liao country asked him to be an assistant, so he took over. Just because the Liao master listened to him, he appointed him as a teacher.

People like Feng Dao will be criticized by many people, because Feng Dao has lost the integrity of a loyal minister, and many writers and historians revile him and call him a slave among slaves.

However, in the troubled times of the Five Dynasties, when courtiers or loyal subjects were martyred, or bowed their heads and retired to the mountains, Feng Dao was a special case. In order to realize his ideals and ambitions, he did not hesitate to bear the burden of humiliation and surrender to other kings. In fact, his behavior should be more worthy of recognition than those loyal ministers who died in the mountains or in seclusion. Because Feng Dao, regardless of assisting the monarch, is people-oriented, and his loyalty to the people exceeds his loyalty to the king.