The founder of Koryo and his heirs consolidated control over the peninsula and strengthened its political and economic foundations by more closely following the bureaucratic and landgrant systems of Tang China. The rise of the Kitan Liao tribe in the north, however, threatened the new dynasty. The Liao invaded in 1010 Koryo was engulfed in devastating wars for a decade. After peace was restored, Koryo's inhabitants witnessed nearly a century of thriving commercial, intellectual, and artistic activities parallel to those taking place under the Song Dynasty (960-1279) in China. The Koryo leaders actively sought to imitate the Song's advanced culture and technology. In turn, the Song looked upon Koryo as a potential ally against the tribal invaders to whom it had been forced to abandon northern China in 1127. Stimulated by the rise of printing in Song China, Koryo also made great headway in printing and publication, leading to the invention of movable metal type in 1234, two centuries before the introduction of movable type in Europe.

By the twelfth century, Koryo was plagued by internal and external problems. Power struggles and avariciousness among the ruling classes led to revolts by their subjects. The situation was aggravated by the rise in the north of the Mongols, who launched a massive invasion in 1231. The Koryo armies put up fierce resistance but were no match for the highly organized mounted troops from the north, whose forces swept most of the Eurasian continent during this period.

The Mongol Empire under Khubilai Khan enlisted Koryo in its expeditions against Japan, mustering thousands of Korean men and ships for ill-fated invasions in 1274 and 1281. In each instance, seasonal typhoons shattered the Mongol-Koryo fleets, giving rise to the myth of kamikaze, or the "divine wind." Korea, in the meantime, was completely under Mongol domination. Koryo kings married Mongol princesses. Only in the early fourteenth century, when the Mongol Empire began to disintegrate and the Ming Dynasty (1368-1644)--founded by a former Chinese peasant--pushed the Mongols back to the north, did Koryo regain its independence. In 1359 and 1361, however, Koryo suffered invasions by a large number of Chinese rebel armies, known as the Red Banner Bandits, who sacked and burned the capital at Kaesong, just north of the mouth of the Han River. The country was left in ruins.

As the Mongols retreated to the north and the Ming established a garrison in the northeastern part of the Korean Peninsula, the Koryo court was torn between pro-Ming and pro-Mongol factions. General Yi Song-gye, who had been sent to attack the Ming forces in the Liaodong region of Manchuria, revolted at the Yalu and turned his army against his own capital, seizing it with ease. Yi took the throne in 1392, founding Korea's most enduring dynasty. The new state was named Choson, the same name used by the first Korean kingdom fifteen centuries earlier, although the later entity usually has been called simply the Choson Dynasty or the Yi Dynasty. The capital of Choson was at Seoul.

Data as of June 1990