This study aims to research how the southern territories of Baekje(百濟) was changed in the Ungjin Period.
First of all, the period of King Dongseong(東城王), the southern area of Baekje started to advance into Irim(爾林; Imsil) in the upper area of Seomjin River(蟾津江) in the 9th of King Dongseong and into Gwangju(光州) and Naju(羅州) in the 17th(495). Then, in the 20th, Baekje subdued Tammora(耽牟羅; Gangjin ＆ Haenam), and 10 years after that, Tamra(耽羅; Jejudo) on the southern ocean, also, was subdued.
During the reign of King Muryeong(武寧王), Baekje attacked against the great Gaya and expanded its territory to the areas of the Seomjin River ranging from Gimun(己汶; Namwon) to Daesa(帶沙; Hadong). This means the achievement of the southern policy that Baekje aggressively had developed after the transfer of the capital to Wungjin. Futhermore, the occupation of Daesa(Hadong) means having a command of the communication with Wae(倭) through the Southern Sea and securing the strategic bridgehead to advance to the areas of the Nakdong River, including Jinju and Haeman.
As a result, during the reign of King Dongseong and King Muryeong, overcame the confusing periods of King Munju(文周王) and King Samgeun(三斤王) and more firmly expanded their territory to the province of Jeollado(全羅道) in the south, and Baekje got the recognition that ‘Baekje became a powerful country' from surrounding countries.