Genghis Khan (1162-18 August 1227), born Temujin, was the Khan of the Mongol Empire from 1206 to 1227, preceding Tolui Khan/Ogedei Khan. Temujin united the tribes of Mongolia and formed the Mongol Empire, ravaging China and creating a vast empire stretching from northern China in the east to the Black Sea in the west. His name "Genghis Khan" means "universal ruler", and was a title that he adopted when he united the Mongols as an empire. Regarded as one of the greatest conquerors in history, Genghis Khan created an infrastructure for his government and his military, and he made a whole new system that Mongols followed for hundreds of years. Genghis Khan destroyed the Kara-Khitans, Khwarezmian Empire, and several Russian states, while also launching an invasion of the Jin dynasty and Xi Xia of northern China that carried on after his death. In 1227, he died at the age of 65 of natural causes, although it was rumored that he may have been poisoned or mortally wounded in battle.
The founder of the Mongol Empire was originally named Temujin, the son of the chieftain of one of the many nomadic tribes that inhabited what is now Mongolia. Temujin's father was murdered when he was a child and he grew up as a tough survivor in a hostile environment. Success in the raids and skirmishes of endemic tribal warfare made him the leader of a growing warrior band and allowed him to form valuable alliances with tribal leaders. By establishing his authority over his friends and defeating his enemies, he extended his control over the fragmented tribes until, in 1206, he was acknowledged as khan (ruler) of the united peoples of the steppe.
As Genghis Khan he harnessed the energy of intertribal war to launch a campaign of conquest. His first target was the Tangut empire in western Xia (now northwestern China). First invaded in 1209, the Tanguts were absorbed into the Mongol empire in the last years of Genghis's reign. Farther south lay the territory of the Jin Dynasty, descendants of Jurchen steppe horsemen who ruled northern China from Zhongdu (now Beijing). Genghis attacked them in 1211, but was blocked by the defenses of their walled cities. He returned with a siege train in 1214 and captured Zhongdu the next year, although the Jin were only conquered under Genghis's successors.
The Mongols also struck westward into Mongol-ruled central Asia. The shah of the Khwarezmian Empire - which stretched from Iran to Uzbekistan - had executed a Mongol ambassador, provoking an invasion that crushed the great cities of Samarkand and Bukhara. By the time Genghis died in 1227, his armies had swept as far west as the shores of the Black Sea.