the maintenance of the sovereign power and traditional culture of Goryeo, implying that the Mongols gave up incorporating Goryeo under direct Mongolian control and were content to give Goryeo autonomy, but the king of Goryeo must marry a Mongolian princess and be subordinate to the Mongolian Khans. Ninth Mongol invasion of Korea Aftermath Much of Goryeo was devastated after the decades of fighting. It was said that no wooden structures remained afterward in Goryeo. There was cultural destruction, and the nine-floor-tower of Hwangnyongsa and the first Tripitaka Koreana were destroyed. After seeing the Goryeo crown prince come to concede, Kublai Khan was jubilant and said "Goryeo is a country that long ago even Tang Taizong personally campaigned against but was unable to defeat, but now the crown prince comes to me, it is the will of heaven!" Internal struggles within the royal court continued regarding the peace with the Mongols until 1270. Since Choe Chung-heon, Goryeo had been a military dictatorship, ruled by the private army of the powerful Choe family. Some of these military officials formed the Sambyeolcho Rebellion (1270–1273) and resisted in the islands off the southern shore of the Korean peninsula. Beginning with Wonjong, for approximately 80 years, Goryeo was a vassal state and compulsory ally of the Yuan dynasty. The Mongol and Korean rulers were also tied by marriages as some Mongol prince and aristocrats married Korean princesses and vice versa. During the reign of Kublai Khan, King Chungnyeol of Goryeo married one of Kublai's daughters. Later, a Korean princess called the Empress Gi became an empress through her marriage with Toghon Temür, and her son, Ayushiridara became an emperor of the Northern Yuan dynasty. The Kings of Goryeo held an important status like other important families of Mardin, Uyghurs and Mongols (Oirat, Hongirat, and Ikeres). It is claimed that one of Goryeo monarchs was the most beloved grandson of Kublai Khan and had grown up at the Yuan court. The Mongol darughachis at the court of the Goryeo were offered provisions and sometimes were also willing to actively involved in the affairs of the Goryeo court. Part of Jeju Island converted to a grazing area for the Mongol cavalry stationed there. Even today, there are several Mongolian words used in the Jeju Island. Furthermore, the Mongol domination of Eurasia encouraged cultural exchange, and this would include for example the transmission of some of the Korean