Goryeo was invaded from the Mongols in seven key strategies with the 1230s until the 1270s, but was by no means conquered.[117] Exhausted right after a long time of fighting, Goryeo despatched its crown prince into the Yuan cash to swear allegiance to the Mongols; Kublai Khan accepted, and married certainly one of his daughters for the Korean crown prince,[117] as well as the dynastic line of Goryeo continued to survive beneath the overlordship in the Mongol Yuan dynasty being a semi-autonomous vassal condition and Obligatory ally.
However the Sui Military 파라곤솔루션 was lured into a trap because of the famed Koguryŏ commander Ŭlchi Mundŏk, and suffered a calamitous defeat at the Salsu (Ch'ŏngch'ŏn) River. It is claimed that only 2,seven-hundred in the three hundred,000 Sui troopers who had crossed the Yalu survived to search out their way back, as well as Sui emperor now lifted the siege of Liao-tung Fortress and withdrew his forces to China suitable. Yang Ti continued to send out his armies towards Koguryŏ but all over again with no achievement, and in advance of extended his war-weakened empire crumbled." ^