The conquest was realised in 395 by the Great King Gwang-Gae-To himself over Biryo which was the old Pilryo part, one of the ancient Khitan eight parts around the Sira Muren riverside. The conflicts between Jaycan and Koguryo produced in A.D. 479 the division of Didouyu to which the scholars agree nowadays as the area around the Xilingol League, the largest step area in the inner Mongolia. By this division, Koguryo deconstructed the ancient Khitan eight parts, so the diverse groups of Khitan either escaped to North Wi or became dominated by Koguryo. In 581~600 A.D. the rivalities between Koguryo, Turk and Sui over the Khitan groups became deepened in East Mongolia. And the Wuchanzhen warlords, the military group for the Sui and Tang Empire, worried about the Koguryo’s desperate pursuit of the hegemony over Mal´Gal and Khitan. So we can postulate these rivalities as one of the major causes for the war between Koguryo and Sui-Tang.
Ⅰ. 序言
Ⅱ. 高句麗의 東蒙古 進出(A.D.4 C 末~A.D. 5 C)
Ⅲ. ‘地豆宇瓜分(479 A.D.)’을 前後한 고구려의 동몽고 經略
Ⅳ. 동몽고에서의 고구려와 諸列强의 勢力競合相(A.D. 5C 末 以後)
Ⅴ. 結語
[Abstract]