Consideration
Koryo was the country that ruled the Korean Peninsula for 474 years until the fall of the Joseon Dynasty in 1392 after the founding of King Wonjae in 918. At the end of the Silla period, King Wang Geon, a member of the Songak family, opened in 918, and in 919, he corrected the name Songak as a city park and made it the capital. After that, he reunited the Korean peninsula in 936. In order to establish the stability of the kingdom and the central power system, he established the noble sword method and the past system, and strengthened his kingship by removing the powers and enemies. Then, at the time of the King Sejong, the exhibition and the system were carried out, and the Sungjong regulated the ruling system. In the outskirts of the capital city, Boryando, he traded with merchants such as Song Dynasty, Why, Arabia, Persia and Rome. Through the war with the nomadic empire, Yonara and the Kwang, they maintained a balance of power in the three-river structure of Goryeo-Yo-North Song, Goryeo-gold-South Song in the East Asian international order and established a friendly relationship with the Song dynasty.