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!" Part of Jeju Island converted to a grazing area for the Mongol cavalry stationed there. The Goryeo dynasty survived under influence of the Mongol Yuan Dynasty until it began to force Mongolian garrisons back starting in the 1350s, when the Yuan Dynasty was already beginning to crumble, suffering from massive rebellions in China. Taking advantage of the opportunity, the Goryeo king Gongmin also managed to regain some northern territories.