several victories but the Goryeo military and Righteous armies could not withstand the waves of invasions. After the Mongols were unable to take either Ganghwa Island or Goryeo's mainland mountain castles, the Mongols began to burn Goryeo farmland in an attempt to starve the populace. When some fortresses finally surrendered, the Mongols executed everyone who resisted them. In 1238, Goryeo relented and sued for peace. The Mongols withdrew, in exchange for Goryeo's agreement to send the Royal Family as hostages. However, Goryeo sent an unrelated member of the Royal line. Incensed, the Mongols demanded to clear the seas of Korean ships, relocate the court to the mainland, the hand-over of anti-Mongol bureaucrats, and, again, the Royal family as hostages. In response, Korea sent a distant princess and ten children of nobles. Fourth Mongol invasion of Korea (July 1247 – March 1248) In 1247, the Mongols began the fourth campaign against Goryeo, again demanding the return of the capital to Songdo and the Royal Family as hostages. Güyük sent Amuqan to Korea and the Mongols camped near Yomju in July 1247. After the king Gojong of Goryeo refused to move his capital from Ganghwa island to Songdo, Amuqan's force pillaged the Korean Peninsula. With the death of Güyük Khan in 1248, however, the Mongols withdrew again. But the Mongol raids continued until 1250. Fifth Mongol invasion of Korea (July 1253 – January 1254) Upon the 1251 ascension of Möngke Khan, the Mongols again repeated their demands. Möngke Khan sent envoys to Goryeo, announcing his coronation in October 1251. He also demanded the King Gojong be summoned before him in person and his headquarters be moved from Ganghwa Island to the Korean mainland. But the Goryeo court refused to send the king because the old king was unable to travel so far. Möngke again dispatched his envoys with specific tasks. The envoys were well received by the Goryeo officials but they also criticized them, saying their king did not follow his overlord Möngke's orders. Möngke ordered the prince Yeku to command the army against Korea. However, a Korean in the court of Möngke convinced them to begin their campaign in July 1253. Yeku, along with Amuqan, demanded the Goryeo court to surrender. The court refused but did not resist the Mongols and gathered the peasantry into the mountain fortresses and islands. Working together with the Goryeo commanders who had joined the Mongols,