He was born in 1162, near the border of Mongolia and Siberia. His mother was kidnapped by his father and forced into marriage.
Expansion under Genghis Khan
In 1178, at age 16, Temijun got married to Borte. They had many kids. This wasn't his only marriage. During this time, he killed his brother and took over as head of the poverty-stricken household.
In 1206, a Mongol tribal assembly recognized Temujin as Genghis Khan. Means "universal" or "supreme" ruler.
The death of Genghis Khan
There were two major reasons why expansion occurred under his ruling. The Mongols needed a common task or they would fragment and fall apart. He needed external resources with which to reward his followers.
Genghis Khan reorganized the entire social structure of the Mongols into military units. As a result of the conquered civilizations, all Mongols benefited from the wealth.
In 1227, Genghis Khan died. The cause of the death remains a mystery but people believe he died as a result of the actions again the Weestern Xia, illness, falling from his house, and wounds from battle.