For people from Goguryeo, Anseung was under control of Silla by protecting him as King of Goguryeo and then King of Bodeok, but King Munmu put much effort into integration of the former three kingdoms by having his younger sister marry Anseung in 680 to unite the two royal families of Silla and Goguryeo.
また、高句麗移民に対しては安勝を保護して高句麗王、次いで報徳王として新羅の配下に冊封していたが、680年には文武王の妹を安勝に降嫁させて新羅・高句麗の王家の結合を図り、旧の三国が一体となるように努めた。