Chaghatay Khān (r. 624-42/1227-44) was Chinggis Khān's second son by his chief wife, Börte, and the ancestor of the Chaghatayid khān s who ruled Central Asia until 771/1370 and Moghulistan (eastern Central Asia, southern Kazakhstan, and Xinjiang) until 1088/1677. With his brothers Jochi and Ögödei, Chaghatay took part in his father's campaigns in northern China (607-12/1211-6) and in Central Asia, conquering Utrār (616/1219) and Khwārazm (617-8/1220-1), and building bridges and roads in Central Asia to facilitate