Chungnyeol of Goryeo

King Chungnyeol of Goryeo (3 April 1236 – 30 July 1308) was the 25th ruler of the medieval Korean kingdom of Goryeo from 1274 to 1308. He was the son of Wonjong, his predecessor on the throne. Chungnyeol was king during the Mongol Invasions of Japan, aiding in the offensives.
Biography.
King Chungnyeol was the first Goryeo ruler to be remembered by the title "wang" (王), meaning "king". Previous rulers had received temple names with the suffix "jo" (祖) or "jong" (宗), meaning "revered ancestor" and a title typically reserved for emperors. After Goryeo became a vassal of the Mongol Yuan dynasty, Yuan emperor Kublai Khan perceived this practice as lowering his own power and ordered that the Goryeo rulers could not receive such names henceforth.
King Chungnyeol, as Crown Prince Sim, proposed to marry a daughter of Kublai Khan. Kublai Khan agreed and for more than 80 years, Goryeo kings married members of Mongol royalty. Heirs to the throne were given Mongol names and were sent to Dadu where they were raised until they reached adulthood.
King Chungnyeol is also known as the fixer who instigated Mongol Emperor to invade Japan with voluntary and overall naval aid to invade Japan together with Mongol Empire.