There is no direct extant record about Namhansanseong dating from the Goryeo Dynasty.
However, the epitaph of Gwangju County Magistrate Yi Se-hwa includes the statement that “The inhabitants of Gwangju county fled to Gwangjuseong Fortress and fought against the Mongol army during the first Mongol invasion of Korea in 1231. Then, during the second Mongol invasion of Korea in 1232, when the Mongol’s main unit led by General Saritai attacked Gwangjuseong Fortress, Yi Se-hwa defeated them.”
Based on these facts, it is believed that Gwangjuseong Fortress was a strategic point close to the town, making it an advantageous position for the local people to enter and defend.
At present, the major fortresses located in the vicinity of Gwangju include Iseongsanseong and Namhansanseong.
Iseongsanseong was built by the Silla Dynasty in the mid-sixth century, and was a strategic point. However, as it was small in scale and located only 209 m above sea level, it was little more than an advance base for offensive purposes and a local administrative center, rather than a place where numerous people could take shelter for a long period.
On the other hand, Namhansanseong was an impregnable fortress with a large interior area, making it advantageous for dealing with a large enemy force.
In addition, judging from the fragments of Goryeo era roof tiles excavated from the fortress, Namhansanseong is believed to have been used during the Goryeo period as well.
Therefore, it is believed that the fortress recorded as Gwangjuseong in the Goryeo period definitely refers to Namhansanseong.