Karakorum (Khalkha Mongolian: Хархорум, Kharkhorum; Mongolian Script:, Qaraqorum; ) was the capital of the Mongol Empire between 1235 and 1260 and of the Northern Yuan dynasty in the 14–15th centuries. Its ruins lie in the northwestern corner of the Övörkhangai Province of modern-day Mongolia, near the present town of Kharkhorin and adjacent to the Erdene Zuu Monastery, which is likely the oldest surviving Buddhist monastery in Mongolia. They are in the upper part of the World Heritage Site Orkhon Valley. The Orkhon valley was a center of the Xiongnu, Göktürk, and Uyghur empires. To the Göktürks, the nearby Khangai Mountains had been the location of the Ötüken (the locus of power), and the Uyghur capital Karabalgasun was located close to where later Karakorum would be erected (downstream the Orkhon River 27 km north–west from Karakorum). This area is probably also one of the oldest farming areas in Mongolia. In 1218–1219, Genghis Khan rallied his troops for the campaign against the Khwarazmian Empire in a place called Karakorum, but the actual foundation of a city is usually said to have occurred only in 1220. Until 1235, Karakorum seems to have been little more than a yurt town; only then, after the defeat of the Jin empire, did Genghis' successor Ögedei erect city walls and build a fixed palace. Ögedei Khan gave the decree to build the Tumen Amgalan Ord (Palace of Myriad Peace; Wan'angong in Chinese) in 1235 the year after he defeated the Jin dynasty. It was finished in one year. In the History of Yuan (元史), it is written in the section for Taizong (太宗) Ögedei Khan: "In the seventh year (1236), in the year of the blue sheep the Wan'angong (萬安宮) was established in Helin (和林, Karakorum)." One of Genghis Khan's nine ministers, Yelü Chucai (1190–1244), said the following poem during the ridge raising ceremony of the Tumen Amgalan Ord: "Installed ridge well fit and stone foundation, The parallel placed majestic palace has been raised, When the bells and drums of the Lord and officials sound pleasantly, The setting sun calls the horses of war to itself from the mountain peaks.