King Chungnyeol of Goryeo

King Chungnyeol provided Goryeo ships, troops, and supplies for the first Mongol invasion of Japan. Goryeo forces suffered heavy losses in the failed campaign, which ended with the destruction of the fleet by a typhoon. This strained Goryeo's resources and population.

King Chungnyeol married Princess Jeguk, a daughter of Kublai Khan, becoming the first Goryeo king to take a Mongol wife. This marriage formalized the Mongol-Goryeo alliance and made Chungnyeol a Mongol son-in-law (kuregen), strengthening ties with the Yuan dynasty.

King Chungnyeol ordered Goryeo officials to adopt Mongol hairstyles and clothing, and introduced Mongol court ceremonies. This policy aimed to appease the Yuan court but caused resentment among Korean nobles who saw it as a betrayal of Korean identity.

King Chungnyeol again mobilized Goryeo's navy and army for the second Mongol invasion of Japan. The campaign ended in disaster when a typhoon (kamikaze) destroyed the combined Mongol-Goryeo fleet, resulting in massive casualties and further draining Goryeo's economy.