Yuan interference, King Gongmin and the end of Goryeo

Sent to attack Liaodong in 1388, Yi Seong-gye turned his army around at Wihwa Island in the Amnok River; four years later he was king.

After 1270 Goryeo kept its kings, its laws and its name, but it lived under the shadow of the Yuan, the dynasty Kublai Khan founded in 1271. Kings married Yuan princesses; the first was King Chungnyeol, whose wife was a daughter of Kublai. Mongol offices on Goryeo soil watched over the court, and the Mongols ruled some border regions directly. One of these, the Ssangseong Commandery in the northeast, was set up in 1258 when two Goryeo men went over to the Mongols with the land they controlled. Historians call these decades the period of Yuan interference; some date it from the peace of 1259, others from the return to Gaegyeong in 1270.

King Gongmin breaks away

By the 1350s the Yuan was weakening. King Gongmin, though married to a Yuan princess himself, moved against its hold on Goryeo. In the fifth month of 1356 he purged Gi Cheol and his faction, a faction that owed its power to Empress Gi at the Yuan court and to the Mongols, and he abolished the office through which the Yuan had meddled in Goryeo's affairs. He then turned north. In the seventh month of 1356 Goryeo forces took back the Ssangseong Commandery, ending almost a century of Mongol rule there. A local commander named Yi Ja-chun helped the attack and joined the Goryeo court. His son was Yi Seong-gye.

Red Turbans, pirates and new weapons

Gongmin's later years were troubled. Red Turban rebels from China invaded, and Japanese pirates, the waegu, who had raided now and then since 1223, became a constant menace after 1350, reaching deep inland. Choe Mu-seon, convinced that only gunpowder could stop the pirates, learned how to make it from a Chinese source, and in 1377 the court set up the Hwatong dogam, an office for gunpowder weapons. In 1380 at Jinpo, Goryeo ships used cannon in a sea battle for the first time and destroyed a large pirate fleet.

Wihwa Island and the end

The retreat from Wihwa Island decided the dynasty's fate. Yi Seong-gye and his allies controlled the army and the court, and in 1392 he took the throne himself. Goryeo ended after 474 years, and a new dynasty, Joseon, began. Its story is told in the next course.