Kaidu (Middle Mongol: , Modern Mongol: / , ; ; c. 1230 – 1301) was a grandson of the Mongol khagan Ögedei (1185–1241) and thus leader of the House of Ögedei and the de facto khan of the Chagatai Khanate, a division of the Mongol Empire. He ruled parts of modern-day Xinjiang and Central Asia during the 13th century, and actively opposed his uncle, Kublai, who established the Yuan dynasty. Medieval chroniclers often mistranslated Kadan as Kaidu, mistakenly placing Kaidu at the Battle of Legnica. Kadan was the brother of Güyük, and Kaidu's uncle. Early life Kaidu was the son of Kashin (whose name is also spelled Qashi) and therefore a grandson of Ögedei Khan and Töregene Khatun, and a great-grandson of Genghis Khan and Börte. His mother's name was Shabkana Khatun from the Bekrin (Mekrin) tribe of mountaineers that were "neither Mongols, nor Uighurs". In 1260, Marco Polo described Yarkand, part of the area under Kaidu as "five days' journey in extent"; that its inhabitants were mostly Muslim although there were also some Nestorian and Jacobite Assyrians; and that it had plenty of food and other necessities, "especially cotton." In the Toluid Civil War between 1260 and 1264, Kublai Khan was warring with his own brother Ariq Böke, who was proclaimed Great Khan at Karakorum, Kaidu began to have major conflicts with Kublai and his ally, the Ilkhanate. Meanwhile, the Chagatayid Khan Alghu, who supported Kublai as Khagan, ravaged the lands of Kaidu. This forced Kaidu to make an alliance with Berke, the khan of the Golden Horde. Conquest of Transoxiana After the defeat of Ariq Böke in 1264, Kublai summoned Kaidu to his court, possibly to discuss the future of the empire and give Kaidu his share of the Ögedeid appanage in China. But Kaidu avoided appearing at his court and said that his horses were too thin to bear long distance travel. Because Genghis Khan had made a law that all branches of the family had to approve the granting of the title of Great Khan, Kaidu's enmity was a constant obstacle to Kublai's ambitions. In 1266 Baraq was dispatched to Central Asia to take the throne of Chagatai. Kublai instigated Baraq to attack Kaidu in 1268. At first Baraq defeated Kaidu, however, the former was defeated by the latter with the assistance of Möngke-Temür, successor of Berke. When Baraq advanced towards Kaidu, the latter set a