12 events the sources record for this year, grouped by region.
What happened
China (3)
Li Shiji captured Goguryeo's king Gojang and presented him (in the twelfth month the captives were presented). (New Book of Tang (Xin Tangshu), Annals 新唐書 卷003 高宗 總章1年9月)
In 668, Xue Rengui leads the advance, fights Goguryeo and routs them, killing or capturing more than 10,000, and takes Buyeo castle. (Zizhi Tongjian (Comprehensive Mirror) 권201 668년 항)
In September 668, Li Shiji takes Daehaeng castle; the armies then gather and reach Amnokchaek, where Goguryeo blocks and fights but is routed; they pursue over 200 li and take Sini castle, and many castles flee or surrender. (Zizhi Tongjian (Comprehensive Mirror) 권201 668년 항)
Korean Peninsula (8)
Li Ji defeated Goguryeo and took Pyongyang Fortress, captured King Bojang and Yeon Namgeon, and established the Protectorate General to Pacify the East. (Old Book of Tang (Jiu Tangshu), Annals 舊唐書 卷5 總章1年 9月)
Liu Rengui, carrying the imperial edict, reached Dangham Port, and the king sent Kim Inmun to welcome him with ceremony. (Samguk Sagi (History of the Three Kingdoms) 卷06 文武王 8年)
When Silla's army surrounded Pyongyang together with the great Tang army, the king of Goguryeo sent Namsan to ask for surrender. (Samguk Sagi (History of the Three Kingdoms) 卷06 文武王 8年)
Li Ji went home; Goguryeo was divided into nine protectorates and forty-two prefectures, and the Andong Protectorate-General was set up at Pyongyang. (Samguk Sagi (History of the Three Kingdoms) 卷22 寶藏王下 27年)
In 668, Qibi Heli first reaches the foot of Pyongyang city, and Li Shiji's army follows and besieges it for a little over a month; the Goguryeo king Jang sends 98 leaders, including Yeon Namsan, with white flags to surrender to Li Shiji. (Zizhi Tongjian (Comprehensive Mirror) 권201 668년 항)