長壽王 5年～長壽王 7年 동아시아의 정세와 高句麗의 동향

Abstract

In August of 417, Eastern Jin(東晉) destroyed Eastern Jin(後秦). But the destruction of Eastern Jin had brought about a major change in East Asian dynamics. Eastern Jin did not occupy the territory, population, and resources of Later-Qin(後秦). Xiⲁ(夏) and Northern Wei(北魏) had taken most of Later-Qin(後秦)'s human and physical resources. What draws attention is that Northern Wei‘s capabilities had been strengthened. Northern Wei accepted the Later-Qin(後秦) people and took the territory without sacrifice. This would have inevitably led to the strengthening of the Northern Wei‘s power. It is important to look at the status of Goguryeo on the Korean Peninsula during this time. Around 417 A,D., the ancient kingdoms of Korea were Goguryeo, Baekje (百濟) and Silla (新羅). At this time, Goguryeo was in the ascendant against Baekje. In 417, Haegoo, Baekje's defense minister, supervised the building of the castle of Sagoo. Building a defensive castle of Sagoo showed that Baekje was in a defensive position. Goguryeo had a powerful advantage over Baekje on the Korean Peninsula around this time. Meanwhile, Goguryeo even intervened in the royal change of Silla. As a result, Goguryeo was able to put Silla under a certain influence on the Korean Peninsula. Eventually, Goguryeo had the strongest influence on the Korean peninsula in 417. In 418, the influence of the strengthened Northern Wei was extended to Northern Yan (北燕). Northern Wei attacked Northern Yan in May 418. Northern Yan (北燕) was far behind as a military power against Northern Wei. The remarkable difference in military power was a major factor in Northern Wei's invasion of Northern Yan. If Northern Yan (北燕) is destroyed, Goguryeo is in great danger. Northern Yan was functioning as a buffer zone between Goguryeo and Northern Wei. For this reason, it seems that Koguryo decided to move the capital city from Guknaeseong (國內城) to Pyongyang (平壤). The period is estimated to have been around the year 418 when the Northern Wei encompassed the Capital of Northern Yan. As a result, Goguryeo could not expand the territory until around 418. The capacity of Goguryeo would have been concentrated in the construction of a new capital from this time. In the end, the collapse of Later-Qin in 417 led to the expansion of Northern Wei's capabilities. In 418 Northern Wei invaded the capital of Northern Yan between Goguryeo and Northern Wei. Under these circumstances, Koguryo decided to move the Capital to Pyongyang. To move the capital to Pyongyang, there had to have been a new palace and a new government office, as well as a construction of Pyongyang's fortress and a readjustment of the road network. It took a lot of manpower and resources to move the capital. But in 419 Northern Wei (北魏), Xiⲁ (夏), and Eastern Jin were fighting against each other. Amid the chaotic situation in the Chinese region, Northern Yan (北燕) was functioning as a buffer zone. Goguryeo could have actively pursued a project to move its capital to Pyongyang without pressure from its northwest Due to the massive construction of the capital relocation project, it was difficult for Goguryeo to launch an offensive against Baekje around 418 and 419. At that time, Goguryeo could not afford to take a southward policy aimed at Baekje due to the construction to move the capital to Pyongyang.