Korea () is a region in East Asia ; since 1945, it has been divided into two distinct sovereign states: North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by China to the northwest, Russia to the northeast, and neighbours Japan to the east by the Korea Strait and the Sea of Japan (East Sea ).
Korea emerged as a singular political entity in 676 AD, after centuries of conflict among the Three Kingdoms of Korea, which were unified as Unified Silla to the south and Balhae to the north. Unified Silla divided into three separate states during the Later Three Kingdoms period. Goryeo, which had succeeded Goguryeo, defeated the two other states and united the Korean Peninsula. Around the same time, Balhae collapsed and its last crown prince fled south to Goryeo. Goryeo (also spelled as Koryŏ), whose name developed into the modern exonym "Korea", was a highly cultured state that created the world 's first metal movable type in 1234. However, multiple invasions by the Mongol Empire during the 13th century greatly weakened the nation, which eventually agreed to become a vassal state after decades of fighting. Following military resistance under King Gongmin which ended Mongol political influence in Goryeo, severe political strife followed, and Goryeo eventually fell to a coup led by General Yi Seong-gye, who established Joseon in 1392.
The first 200 years of Joseon were marked by relative peace.
