Genghis Khan was born sometime around 1162 near the Onon river in the north of present-day Mongolia. Named Temujin he was the son of Yesugei the chieftain of the Kiyat a group of families related to the Borjigid clan. His father was murdered at an early age and his mother Oelun-eke went through great hardship. The following decade was full of reversals and Temujin was captured and enslaved and soon after his marriage his wife and Borte was kidnapped and he had to fight to recover her. During these years of hardship he managed to make important friends. The young Boghurchu was his first ally and remained a trusted friend. Temujin restored old alliances with the ruler of the Kereyits and Ong Khan his father's old blood-brother. Temujin remained an ally of Ong Khan and used the alliance to defeat powerful adversaries like Jamuqa and his old friend who had become a hostile foe. The final defeat of the Naiman people and the powerful Jamuqa left Temujin as the dominant in the politics of steppe lands a position that was recognised at an assembly of Mongol chieftains where he was called the Great Khan of the Mongols with the title Genghis Khan the Oceanic Khan or Universal Ruler. Genghis Khan had reorganised the Mongol people into a more effective disciplined military force that facilitated the success of his future campaigns. The first of his concerns was to conquer China divided at this time into three realms the Hsi Hsia people of Tibetan origin in the northwestern provinces and the Jurchen whose Chin dynasty ruled north China from Peking and the Sung dynasty who controlled south China. Longdrawnout battles against the Chin continued but Genghis Khan was satisfied enough with the progress of his campaigns to return to his Mongolian homeland and leave the military affairs of the region to his subordinates. After the defeat in 1218 of the Qara Khita who controlled the Tien Shan mountains north-west of China Mongol dominions reached the Amu Darya and the states of Transoxiana.