The peninsula was not unified soon after Baekje and Goguryeo were destroyed, and as shown in the prior case of April 663 in which Silla was declared Gyerim Great Command Area, where King Munmu served as "governor-general of Gyerim Prefecture," Tang established Ungjin and other command areas in places formerly owned by Baekje, as well as Andong and other military forces in places formerly owned by Goguryeo, in order to have their surviving retainers govern by using the control system for different ethnic groups.
百済・高句麗を滅ぼした後に直ちに半島統一ができたわけではなく、先立って663年4月には新羅もまた鶏林大都督府とされ文武王自身も＜鶏林州大都督＞に任じられていたように、唐は百済の故地には熊津都督府などを、高句麗の故地には安東都護府などを設置し、それぞれの遺臣を用いて統治させるという羈縻政策を用いようとした。