Several years of wandering followed, marked by intertribal kidnapping and feuds, during which time Temujin—who soon became known and feared for his leadership, intelligence and military ability—built up a sizeable following. A tall, strong and hardened young man, with piercing green eyes and a long reddish beard, he finally married Börte at the age of sixteen and was taken under the wing of Toghril Ong-Khan, ruler of the Kerait tribe (and his father’s blood brother). When Börte was later kidnapped by the Merkit tribe, Temujin and Toghril joined forces with Jamuka, a childhood friend of Temujin and now a Mongol chieftain, sending a large army to rescue her. (Börte turned out to be pregnant, and Temujin brought up the child, Jochi, as his own son.) The three-way alliance enabled the Mongols and Keraits to force other tribes into submission.
Following this success, in 1200 Toghril declared Temujin his adoptive son and heir—a fateful decision that enraged both Toghril’s natural son, Senggum, and the ambitious Jamuka, leading ultimately to a war in which Temujin defeated first Jamuka and then Toghril to establish his dominance over the Mongol tribes. In 1206, a council of leading Mongolian tribesmen—called the Kurultai—met and recognized Temujin’s authority, giving him the name Genghis Khan, meaning Oceanic Khan or Ruler of the Universe.
Before 1200, the Mongols had been a scattered people, but Genghis—claiming a mandate from heaven—was swiftly to transform them into a powerful and unified nation. “My strength,” he declared, “was fortified by Heaven and Earth. Foreordained by Mighty Heaven, I was brought here by Mother Earth.” His soldiers were mainly nomadic warriors, including deadly archers who traveled on small but sturdy Mongolian-bred ponies capable of covering great distances. Genghis turned them into a disciplined and brilliantly coordinated war machine that swept all before them.
In 1207—having secured an alliance with the Uighurs and subjugated the Mongols’ old rivals, the Merkit tribe—Genghis immediately began expansionist operations, eating into the Xi Xia territory in northwest China, as well as parts of Tibet. His target was the Silk Road—a key trade route between east and west and the gateway to wealth. In 1211, after refusing to pay tribute to the Jin dynasty in northern China, he went to war again, besieging and destroying the Jin capital, Yanjing, now Beijing, and securing instead tribute for himself. He returned to Mongolia in triumph, taking with him booty, artisans and, above all, guaranteed trade with China.
In 1219, Genghis turned his attentions west after an attack on a caravan of traders he had sent to establish trading links with the Khwarazm empire—a realm including most of Uzbekistan, Iran and Afghanistan under the rule of the sultan Muhammad Khwarazmshah. Genghis showed restraint, but when members of a second Mongolian delegation were beheaded, he raised 200,000 troops and marched into central Asia, with his four sons, Jochi, Ogodei, Chaghatai and Touli serving as commanders. Over the next three years, he subjected the Khwarazm people to a terrifying campaign of shock and awe, taking the cities of Bokhara, Samarkand, Herat, Nishapar and Merv—his troops lining up the civilians of the latter and, in a cold-blooded killing spree, slitting their throats.
A peerless strategist, Genghis recognized the value of fear in building an empire, often sending out envoys to cow enemies into submission through tales of his exploits: civilians slaughtered, money and booty stolen, women raped, molten silver poured into people’s ears. For all this brutality, however, Genghis did not indulge in killing for the sake of it. He was loyal to his friends and generous to supporters, a shrewd manager of men, who promoted an elite of top generals, giving them enormous powers. He spared those who surrendered, reserving wholesale slaughter to make an example of those who resisted. Nor did the Mongols wantonly maim, mutilate or torture—their chief interest was in booty rather than barbarism. Indeed, in some ways Genghis showed himself to be an enlightened ruler, combining political acumen with economic shrewdness. He used divide-and-rule tactics to weaken enemies and promote loyalty. He recognized the importance of good administration, fostering the spread of a unified official language across his empire and a written legal system called Jasagti. He was also tolerant of religions and gave priests an exemption from taxation. Believing in the importance of providing a safe passage of trade between the east and the west, he forbade troops and officials to abuse merchants or citizens, his reign becoming a period of cultural interaction and advancement for the Mongolian people. He was also a patron of artists, craftsmen and literature.