「廣開土王陵碑文」에는 고구려 왕실이 추구했던 방향성이 집약되어 있다. 고구려 건국설화에서 보듯이 고구려 왕실은 北→南으로 쏠리는 공간 관념을 태생적으로 지녔다. 건국자가 개척한 남방은 풍요로운 곳으로서 일종의 未來鄕이었다. 그를 이은 고구려왕들 역시 남방으로의 진출에 대한 이상을 품고 있었다. 또 그것을 구현하는 일이 고구려사의 전개 과정이기도 했다. 능비문에 보면 여러 건의 중요한 전쟁 기사 가운데 대부분이 남방 진출과 연관되어 있었다. 더욱이 광개토왕 일생일대의 戰果처럼 능비문에 기재된 64城의 존재 역시 백제와의 전쟁에 대한 결산이었다. 이러한 사실은 광개토왕대에 추진하였던 전쟁의 방향성이 남방이었음을 웅변해 준다. 능비문에 적혀 있는 광개토왕릉을 지키는 묘지기들의 구성에는 ``百殘南居韓``을 비롯한 백제 영역 바깥의 세력도 포함된 사실이 밝혀졌다. 이 사실은 백제 영향권내 영산강유역의 마한 잔여 세력을 비롯하여 부용된 세력에서도 주민이 차출된 증좌인 것이다. 그렇게 된 동기는 영락 6년에 광개토왕이 승전한 직후 백제왕으로부터 男女 노예 1천여 명을 공납받았을 때 포함된 주민들로 보인다. 고구려는 영역은 광개토왕대에 확정된 것이다. 동쪽은 두만강유역, 북쪽은 송화강유역, 서쪽은 요하, 남쪽은 남한강유역이었다. 그런데 고구려가 631년에 서쪽 경계선으로 천리장성을 축조한 배경은 단순한 군사적인 목적과 그러한 用途에만 있지 않았다. 경계선의 역사적 선언이라는 차원에서 중요한 의미를 지녔던 것이다.

The king Gwanggaeto`s tombstone includes the directions which the royal family of Goguryeo country was seeking for. As it can be seen from the myth of the establishment of Goguryeo, the royal family of Goguryeo originally was keeping the idea of leaning from the North to the South. The Southern region which was explored by the founder of the country was seen as the abundant place and the homeland for the future. It is natural that later Goguryeo kings had kept the ideas of the advance to the South. Moreover, the realization of the advance to the South was the development of the whole Goguryeo history. The majority of the important articles on war inscribed on the tombstone are related with the advance to the South. Furthermore, the existence of the 64 fortresses of which names are put on the tombstone as the king Gwanggaeto`s lifetime military achievements is the result of the war with Baekche. Such facts demonstrate that the direction of the war which was propelled by the king Gwanggaeto was the South. The inscriptions about the grave keepers who would guard the king Gwanggaeto`s grave include the fact that Goguryeo`s influence had overcome even the territory of Baekche, namely it had reached ‘the area of Han who reside to the South of Baekche’. This fact is the corroborative evidence that the outer power recruited the inhabitants remaining from the fallen local powers such as Mahan country around the Yeongsan river territories which were under the influence of Baekche. They seem to be a part of the local inhabitants contributed by the king of Baekche to the king Gwanggaeto in the 6th year of Yeongnak (the 6th year of Gwanggaeto, 396 A.D.) right after Gwanggaeto`s victory in the war. The territory of Goguryeo was finalized by the king Gwanggaeto: The eastern boundaries were defined by the Tyumen river, the northern border was the Songhe river, the western territories were bounded by the Liaohe river, and the southern border was the Namhangang river. However, the construction of the Goguryeo`s great wall on the western border line which began in 631 was not driven only for the military purposes or for the military usage. It had a deeper meaning, namely it was the historical declaration of the border line.