The Koma clan (高麗氏) was an immigrant royal family descended from Goguryeo Prince Go Yak'gwang (高若光) who became known as "Genbu " (玄武若光) and later as "Koma no Jakkō" (高麗若光). He was a son of the 28th and last King of Goguryeo, Bojang. In 666, after a power struggle with his brothers or as refuge from Tang's attack (opinion in dispute), he came to the old capital of Asuka in Japan during the reign of Emperor Tenji. Goguryeo fell to Tang in 668 and in 699 his brother Go Deokmu (高德武) founded Lesser Goguryeo. The characters "高麗" can also be read as "Goryeo" (abbreviation of Goguryeo) instead of Koma.