Goryeo

Goryeo (Korean: 고려; Hanja: 高麗; MR: Koryŏ; pronounced [ko.ɾjʌ]; Middle Korean: 고ᇢ롕〮, romanized: kwòwlyéy) was a Korean state founded in 918, during a time of national division called the Later Three Kingdoms period, that unified and ruled the Korean Peninsula until the establishment of Joseon in 1392. Goryeo achieved what has been called a "true national unification" by Korean historians as it not only unified the Later Three Kingdoms but also incorporated much of the ruling class of the northern kingdom of Balhae, who had origins in Goguryeo of the earlier Three Kingdoms of Korea. According to Korean historians, it was during the Goryeo period that the individual identities of Goguryeo, Baekje and Silla were successfully merged into a single entity that became the basis of the modern-day Korean identity. The name "Korea" is derived from the name of Goryeo, also romanized as Koryŏ, which was first used in the early 5th century by Goguryeo; Goryeo was a successor state to Later Goguryeo and Goguryeo.

Throughout its existence, Goryeo, alongside Unified Silla, was known to be the "Golden Age of Buddhism" in Korea. As the state religion, Buddhism achieved its highest level of influence in Korean history, with 70 temples in the capital alone in the 11th century. Commerce flourished in Goryeo, with merchants coming from as far as the Middle East. The capital in modern-day Kaesong, North Korea was a center of trade and industry. Goryeo was a period of great achievements in Korean art and culture.

During its heyday, Goryeo constantly wrestled with northern empires such as the Liao (Khitans) and Jin (Jurchens). It was invaded by the Mongol Empire and became a vassal state of the Yuan dynasty in the 13th–14th centuries, but attacked the Yuan and reclaimed territories as the Yuan declined. This is considered by modern Korean scholars to be Goryeo's Northern Expansion Doctrine (북진 정책) to reclaim ancestral lands formerly owned by Goguryeo. As much as it valued education and culture, Goryeo was able to mobilize sizable military might during times of war. It fended off massive armies of the Red Turban Rebels from China and professional Japanese pirates in its twilight years of the 14th century. A final proposed attack against the Ming dynasty resulted in a coup d'état led by General Yi Sŏng-gye that ended the Goryeo dynasty.