5. King Gwanggaeto the great Gwanggaeto the Great (374–413, r. 391–413) was the nineteenth monarch of Goguryeo. His full posthumous name means "Entombed in Gukgangsang, Broad Expander of Domain, Peacemaker, Supreme King", sometimes abbreviated to Hotaewang. His era name is Yeongnak and he is occasionally recorded as Yeongnak Taewang ("Supreme King" or "Emperor" Yeongnak). Gwanggaeto's imperial reign title meant that Goguryeo was on equal standing as an empire with the imperial dynasties in China. Under Gwanggaeto, Goguryeo began a golden age, becoming a powerful empire and one of the great powers in East Asia. Gwanggaeto made enormous advances and conquests into: Western Manchuria against Khitan tribes; Inner Mongolia and the Maritime Province of Russia against numerous nations and tribes; and the Han River valley in central Korea to control over two-thirds of the Korean peninsula. In regard to the Korean peninsula, Gwanggaeto defeated Baekje, the then most powerful of the Three Kingdoms of Korea, in 396, capturing the capital city of Wiryeseong in present-day Seoul. In 399, Silla, the southeastern kingdom of Korea, sought aid from Goguryeo due to incursions by Baekje troops and their Wa allies from the Japanese archipelago. Gwanggaeto dispatched 50,000 expeditionary troops, crushing his enemies and securing Silla as a de facto protectorate; he thus subdued the other Korean kingdoms and achieved a loose unification of the Korean peninsula under Goguryeo. In his western campaigns, he defeated the Xianbei of the Later Yan empire and conquered the Liaodong peninsula, regaining the ancient domain of Gojoseon. Gwanggaeto's accomplishments are recorded on the Gwanggaeto Stele, erected in 414 at the supposed site of his tomb in Ji'an along the present-day China–North Korea border. Constructed by his son and successor Jangsu, the monument to Gwanggaeto the Great is the largest engraved stele in the world. Related Historic Site 1. Gwanggaeto Stele_Jian Shi, Tonghua Shi, Jilin Sheng, China 2. Jungwon Goguryeo Stele 3. Village of Blacksmith in Goguryeo Related Historic Site_Address 1. Gwanggaeto Stele - Jian Shi, Tonghua Shi, Jilin Sheng, China Jian Shi, Tonghua Shi, Jilin Sheng, China Related Historic Site_Address 2. Jungwon Goguryeo Stele 280-11 Yongjeon-ri, Gageum-myeon, Cheongju, Chungcheongbuk-do, Republic of Korea Related Historic Site_Address 3. Village of Blacksmith in Goguryeo 41 Uminae-gil, Gyomun 1(il)-dong, Guri-si, Gyeonggi-do, Republic of Korea .