Genghis Khan, the Mongol leader who forged an empire stretching from the east coast of China west to the Aral Sea, dies in camp during a campaign against the Chinese kingdom of Xi Xia. The great Khan, who was over 60 and in failing health, may have succumbed to injuries incurred during a fall from a horse in the previous year.

Genghis Khan was born as Temujin around 1162. His father, a minor Mongol chieftain, died when Temujin was in his early teens. Temujin succeeded him, but the tribe would not obey so young a chief. Temporarily abandoned, Temujin’s family was left to fend for themselves in the wilderness of the Steppes.

By his late teens, Temujin had grown into a feared warrior and charismatic figure who began gathering followers and forging alliances with other Mongol leaders. After his wife was kidnapped by a rival tribe, Temujin organized a military force to defeat the tribe. Successful, he then turned against other clans and tribes and set out to unite the Mongols by force. Many warriors voluntarily came to his side, but those who did not were defeated and then offered the choice of obedience or death. The nobility of conquered tribes were generally executed. By 1206, Temujin was the leader of a great Mongol confederation and was granted the title Genghis Khan, translated as “Oceanic Ruler” or “Universal Ruler.”

Khan promulgated a code of conduct and organized his armies on a system of 10: 10 men to a squad, 10 squads to a company, 10 companies to a regiment, and 10 regiments to a “Tumen,” a fearful military unit made up of 10,000 cavalrymen. Because of their nomadic nature, the Mongols were able to breed far more horses than sedentary civilizations, which could not afford to sacrifice farmland for large breeding pastures. All of Khan’s warriors were mounted, and half of any given army was made up of armored soldiers wielding swords and lances. Light cavalry archers filled most of the remaining ranks. Khan’s family and other trusted clan members led these highly mobile armies, and by 1209 the Mongols were on the move against China.

Using an extensive network of spies and scouts, Khan detected a weakness in his enemies’ defenses and then attacked the point with as many as 250,000 cavalrymen at once. When attacking large cities, the Mongols used sophisticated sieging equipment such as catapults and mangonels and even diverted rivers to flood out the enemy. Most armies and cities crumbled under the overwhelming show of force, and the massacres that followed a Mongol victory eliminated thoughts of further resistance. Those who survived–and millions did not–were granted religious freedom and protection within the rapidly growing Mongol empire. By 1227, Khan had conquered much of Central Asia and made incursions into Eastern Europe, Persia, and India. His great empire stretched from central Russia down to the Aral Sea in the west, and from northern China down to Beijing in the east.

On August 18, 1227, while putting down a revolt in the kingdom of Xi Xia, Genghis Khan died. On his deathbed, he ordered that Xi Xia be wiped from the face of the earth. Obedient as always, Khan’s successors leveled whole cities and towns, killing or enslaving all their inhabitants. Obeying his order to keep his death secret, Genghis’ heirs slaughtered anyone who set eyes on his funeral procession making its way back to Karakorum, the capital of the Mongol empire. Still bringing death as he had in life, many were killed before his corpse was buried in an unmarked grave. His final resting place remains a mystery.

The Mongol empire continued to grow after Genghis Khan’s death, eventually encompassing most of inhabitable Eurasia. The empire disintegrated in the 14th century, but the rulers of many Asian states claimed descendant from Genghis Khan and his captains.