What factor contributed to Genghis Khan's expansion of the Mongol

Genghis Khan (1162-1227) was born in a humble home, but he managed to establish the largest land empire in history. After unifying the nomadic tribes of the Mongolian plateau, he conquered huge territories of central Asia and China. His descendants expanded the empire even further, advancing to such far-off places as Poland, Vietnam, Syria and Korea. At their prime, the Mongols controlled between 11 and 12 million square miles, an area about the size of Africa. Many people were slaughtered in the course of Genghis Khan's invasions, but he also granted religious freedom to his subjects, abolished torture, encouraged trade and created the first international postal system. Genghis Khan died in 1227 during a military campaign against the Chinese kingdom of Xi Xia.

Going against custom, Temujin, as he was known by his people, put competent allies rather than relatives in key positions and executed the leaders of enemy tribes while incorporating the remaining members into his clan. He ordered that all looting wait until after a complete victory had been won, and he organized his warriors into units of 10 without regard to kin. Though Temujin was an animist, his followers included Christians, Muslims and Buddhists. By 1205 he had beat all rivals, including his former best friend Jamuka. The following year, he called a meeting of representatives from every part of the territory and established a nation similar in size to modern Mongolia. He was also proclaimed Chinggis Khan, which roughly translates to "Universal Ruler," a name that became known in the West as Genghis Khan.

Having united the steppe tribes, Genghis Khan ruled over some 1 million people. In order to suppress the traditional causes of tribal warfare, he abolished inherited aristocratic titles. He also forbade the selling and kidnapping of women, banned the enslavement of any Mongol and made livestock theft punishable by death. Moreover, Genghis Khan ordered the adoption of a writing system, conducted a regular census, granted diplomatic immunity to foreign ambassadors and allowed freedom of religion well before that idea caught on elsewhere.

There were several keys to Temujin's great success, but the two most important aspects were presented in the previous paragraphs:

First, he went against custom and did not place relatives in key positions. Second, he instilled order by prohibiting former disruptive behavior such as inheriting tittle, kidnapping and selling women, envisaging Mongol people, and making livestock theft punishable with death.