The trend of historical development at the end of Northern Wei was a race to establish political power by rivaling warlords in the name of “the great duty between monarch and subject”. Gao Huan was able to defeat the Erzhu clan because he was deeply popular through upholding the principle of “the Great Duty between Monarch and Subject”. And the reason why Yuwen Tai was able to beat Houmochen Yue and make Emperor Xiaowu enter guan zhong and establish the Western Wei was also that he followed the same pattern. Although Eastern Wei was a powerful nation, the confidence of its people was shaken due to the forced escape of Emperor Xiaowu. In View of this, Gao Huan was extremely respectful to the monarch and rather permissive towards corruptions. He repeatedly conducted military campaign against Western Wei in attempts to strengthen the legitimacy of his rule. Although Western Wei was weaker in its national strength, it was considered by its contemporary society at large as the legitimate political power representing the Northern Wei. By “controlling the emperor”, Yuwen Tai could claim to “follow the people's will”, “subdue powerful lords”, and “attract the talents”. It helped Yuwen Tai to establish his political power in the early stage and build the foundation to rival Eastern Wei in the long run.