some authors wrote that the three sisters "married emperors" or "married into imperial families". at the time of their marriages, none of their husbands was a member of the imperial family (yet): each of the three sisters became an empress or a posthumous empress after a dynasty change. out of the three dynasty changes, only the first — the usurpation of the western wei throne by the yuwens — is considered a long time coming in which the dugus played no role. in both yang jian's and li yuan's (emperor gaozu of tang) rise to power, family ties to the ruling house (through the sisters and dugu qieluo's daughter yang lihua) were important.