東晉肇建，王氏家族立有大功，時人語云：「王與馬共天下」，這不僅反映出當時的政治實況是「祭則司馬，政由王氏」，也意謂著王家與司馬睿在此前合作創業的過程中，司馬睿是依賴王家方得以居大位。司馬睿雖有血胤的優勢，但政治實力不足，他能南渡，是王家精心挑選，並且與之共謀建國大業，而「王與馬共天下」極有可能是雙方的政治妥協與默契。王家因為與司馬睿共成天下、共治天下，所以「王與馬共天下」並非其他後繼掌權家族可以代換的一種政治模式，他們雖然想與司馬氏共治天下，但他們均無王家與司馬氏共成天下的歷程，所以「王與馬共天下」這種格局只適用於王家，並促使王家成為國史上最有權勢的家族特例。

The Wangs have done a tremendous job assisting the establishment of the East-Jing dynasty. The people back then believe: “The Wangs and the S-Ma rule the dynasty together,” more practically the S-Ma owns the throne, and the Wangs hold the political power. S-Ma acquires his throne accompanied by Wangs’ support. Even though S- Ma has the advantage of the imperial breed; he is not equipped with vanes political power. The Wangs pick S-Ma as the One and help him to move south across the Yang-Zi Rivermake him finally becomes the first emperor of East-Jing. Therefore, the Wangs and S-Ma rule the dynasty together can be a tacit understanding between them. The Wangs can become the family which rule the dynasty with S-Ma is a special political form, which cannot be substituted by any other family because of the history of assisting each other between S-Ma and the Wangs from the beginning. Therefore, this special political relationship makes the Wangs become one of the most powerful families among the Chinese History.