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, reluctantly 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-led Yuan dynasty, the 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, who became the Crown Prince Sim(諶) in 1260, proposed to marry a daughter of Kublai Khan in 1271, which Kublai Khan agreed. Since then, 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. Reign The Khan's son-in-law After Wonjong's death in 1274, Wang Geo (Chungnyeol) rose to power as the 25th King of Goryeo. He was the first Goryeo king with the degraded title forced upon by the Mongols according to Goryeo's submission to vassal status after its 28 years of fierce resistance against the Mongol Empire. As King Chungnyeol became the son-in-law of Kublai Khan and Goryeo the vassal of the Yuan Dynasty, political interference by Yuan Dynasty furthered on towards Goryeo court. Despite these conditions, King Chungnyeol endeavored to maintain national independence and strengthen autonomy guaranteed by Kublai. One of his achievements was having territories like Dongnyeong and Tamra Prefectures lost during the war against the Mongols returned through negotiations. Also, he made it clear to the Yuan Dynasty of which Goryeo will be exercising the rights to keep its traditions and customs in accordance to the promises made twenty years ago by Kublai himself to Wonjong after submission. King Chungnyeol visited the Yuan Dynasty again in 1278, to have the Mongols withdraw its darughachis and troops stationed in Goryeo on the pretext of Kublai's promise 20 years ago. Troops or officials from the Yuan Dynasty were no longer stationed in Goryeo in the aftermath. These rights and requests enabled were partially attributed to the