By the Ming called Wala 瓦剌, by the Qing Elute Menggu 厄魯特蒙古 or Weilate 衛拉特, probably identical to the Turkic Kalmyk (Kalmük) branch, roaming the western area of modern Mongolia, around the upper Jennisey River. At the begin of the Ming period 明 the Oirats under the leadership of Möngke Timur 猛哥帖木兒 rebelled against the Ming empire but accepted the sovereignity of the Chinese empire in 1408, and their chieftains were enfeoffed as kings. King Mahmud "Mahamu 馬哈木" took the chance of the Ming's campaign agianst the Tatars and occupied territory more to the east. In 1412 he even attacked the Ming garrisons. His son "Tuohuan 脫懽" killed the other Oirat kings and united the Mongol forces, with "Tuotuo Buhua 脫脫不花", a descendant of the last Yuan emperor, as Qaghan. His follower "Yexian 也先" undertook a large campaign against the Ming in 1439, defeated the Ming troops at Ft. Tumu 土木堡 and captured Emperor Yingzong 明英宗 (the Zhengtong Emperor 正統皇帝). A few years later Yexian killed Tuotuo Buhua Qaghan but was murdered himself in 1455. After his death the power of the Oirats soon declined although they often staged raids against the Chinese settlements in the western region. Some 150 years later two chieftains again united the forces of the Oirat: Halahula 哈剌忽喇 of the Chuoluosi 綽羅斯部 and Baibagas 拜巴噶斯 of the Heshuote tribe 和碩特部. The four main tribes were Zhunggar 準噶爾部 (=Chuoluosi 綽羅斯部), Durbot 杜爾伯特部, Heshuot 和碩特部 and Turhut 土爾扈特部. The national assembly of the four tribes was called qiurgan 丘爾干 and served as a kind of parliament under the supreme chieftain. The first national chieftains were Bobei Mirza 博貝密爾咱, Haninuoyan Hongguor 哈尼諾顏洪果爾, and Baibagas 拜巴噶斯. In the 1620es Halahula from the Zhunggar could acheive the highest leadership after defeating his opponents among other tribes. He created a federation with the Khalkha Mongols, promulgated a common Oirat-Mongolian law book, the Xinchalü bicek 新察律必扯克, and adopted Lamaism as the Oirat religion. In the next decades, some tribes of the Oirat migrated to the west, some to the Qinghai plateau, and the Zhunggar remained the main represantative of the Oirat, especially after Galdan 噶爾丹 adopted the title of Qaghan in the 1670es. From 1755 to 1757 the Qing 清 armies appeased the northwestern region and reorganized the Oirat in a banner-union system.