Chinese forces under general Li Shiji besiege the strategic fortress city of Anshi (Liaoning) during the Goguryeo-Tang War.

The GoguryeoTang War occurred from 645 to 668 and was fought between Goguryeo and the Tang dynasty. During the course of the war, the two sides allied with various other states. Goguryeo successfully repulsed the invading Tang armies during the first Tang invasions of 645648. After conquering Baekje in 660, Tang and Silla armies invaded Goguryeo from the north and south in 661, but were forced to withdraw in 662. In 666, Yeon Gaesomun died and Goguryeo became plagued by violent dissension, numerous defections, and widespread demoralization. The TangSilla alliance mounted a fresh invasion in the following year, aided by the defector Yeon Namsaeng. In late 668, exhausted from numerous military attacks and suffering from internal political chaos, Goguryeo and the remnants of Baekje army succumbed to the numerically superior armies of the Tang dynasty and Silla.

The war marked the end of the Three Kingdoms of Korea period which had lasted since 57 BC. It also triggered the SillaTang War during which the Silla Kingdom and the Tang Empire fought over the spoils they had gained.

Chinese military general and politician

Li Shiji (594 – December 31, 669), courtesy name Maogong, posthumously known as Duke Zhenwu of Ying, was a Chinese military general and politician who lived in the early Tang dynasty. His original family name was Xú, but he was later given the family name of the Tang imperial clan, Li, by Emperor Gaozu, the Tang dynasty's founding emperor. Later, during the reign of Emperor Gaozong, Li Shiji was known as Li Ji (i.e. the "Shi" in his name was omitted) to avoid naming taboo because the personal name of Emperor Gaozong's predecessor, Emperor Taizong (Li Shimin), had the same Chinese character "Shi". Li Shiji is also referred to as Xu Maogong (his original family name and his courtesy name combined) and Xu Ji in the historical novels Shuo Tang and Sui Tang Yanyi.

Li Shiji was initially a follower of Li Mi, one of the rebel rulers rebelling against the preceding Sui dynasty, and he submitted to the Tang Empire after Li Mi did so, upon which Emperor Gaozu, impressed with his loyalty to Li Mi, granted him the family name "Li". He later participated in destroying Xu Yuanlang and Fu Gongshi, two of the Tang Empire's competitors in the campaign to reunify China. During the reign of Emperor Gaozu's son and successor, Emperor Taizong, Li Shiji participated in the successful campaigns against the Göktürks and Xueyantuo, allowing the Tang Empire to become the dominant power in eastern Asia, and also served as a chancellor. During the reign of Emperor Gaozong, he served as chancellor and the commander of the army against Goguryeo, destroying Goguryeo in 668. He died the next year. He and Li Jing were considered the two most prominent early Tang generals.