Born c. 1162

Died 1227

Mongolian chieftain and conqueror

No empire in history has ever been as large as that conquered in the 1200s by the Mongols, who began their conquests as a simple nation of shepherds and nomads in Central Asia. What welded them into a mighty fighting force was not a religion, or a political belief, or even a shared need for land or food; it was a man, a severe but shrewd warlord known to history as Genghis Khan.

The son of a chieftain

Today Mongolia is a quiet, underpopulated, and underdeveloped land to the north of China. For centuries, it had been home to a hardy nomadic people who had no written language or—until the Middle Ages—cities of their own. The man who briefly made Mongolia the most powerful nation on Earth was born with the name Temujin (TIM-yuh-jin) in 1162.

According to legend, Temujin came into the world grasping a lump...