For more than 100 years, a single family controlled a territorial empire stretching as far as 23 million square kilometers (nine million square miles), from East Asia to Europe. That family was descended from the great warrior Genghis (also spelled Chinggis) Khan, and its reign is known as the Chinggisid (or Genghisid) Dynasty. The following are profiles of some of the empire’s principal leaders.

Genghis Khan

Genghis Khan (1162–1227 C.E.), the founder of the Mongol Empire, is widely regarded as one of the most successful military commanders in world history. In the year 1206 C.E., Genghis—originally known as Temujin—was in his forties, with his greatest military exploits still ahead of him. By that summer, he had conquered his domestic enemies. He summoned a kuriltai (a meeting of the Mongolian tribal chiefs) at which the nomadic tribes of the Mongolian steppe agreed to unite as a new nation under his leadership, confirming his title as Genghis Khan (universal ruler). With ruthless cunning, he overtook his rivals and rose to become the first Great Khan of the Mongols.

He then began a series of campaigns into neighboring lands, taking control of much of northern China, including its capital at what is now Beijing. Turning west, his armies and their legendary cavalry rampaged through Central Asia and captured vast territories as far as the Caspian Sea and into the Middle East. Crossing the Caucasus Mountains, the Mongols overwhelmed a force led by Russian princes in 1223. By the time Genghis Khan returned to Mongolia in 1225, he controlled much of the Silk Road trade network that facilitated commerce between Europe and Asia.

One important diplomatic tactic Genghis Khan used in his rise to power was marriage—a powerful tool in cementing political alliances. Before he had amassed great power, Genghis Khan approached his key ally Toghril, the khan of the Kereit people, and proposed a match between his son and the khan’s daughter. Toghril’s refusal led to battles between Mongol and Kereit clans. However, Toghril’s brother, Jaka Gambu, agreed to a double-marriage pact. One of Jaka Gambu’s daughters, Sorqoqtani, married the Mongol leader’s son, Tolui, while Genghis Khan himself married another daughter, Ibaqa. However, at the kuriltai of 1206, Genghis Khan publicly divorced Ibaqa after a falling out with her father.

Ogodei Khan

Ogodei Khan (circa 1186–1241) was the third son born to Genghis Khan by his senior wife, Borte. Genghis Khan chose Ogodei as his successor, most likely because he had an even temperament and had often made peace when his two older brothers fought. Ogodei’s main task as khan was to preserve and build upon what his father had achieved. Starting in 1229 under Ogodei’s rule, the Mongols extended the boundaries of the empire, with successful campaigns in Persia, the Caucasus, and Russia. He personally led one of the three Mongol armies that captured northern China from the Jin Dynasty in 1234. Ogodei also shifted the Mongol Empire’s tactics from exploitative military occupation toward government and taxation of conquered areas. He built an imperial capital at Karakorum in Mongolia during the 1230s and constructed a highly effective relay system to transmit messages across the vast distances of Eurasia.

Ogodei was a heavy drinker and his increasingly severe addiction made it necessary for him to lean on trusted advisors, including his wife, in matters of policy and administration. He died after a bout of excessive drinking in December 1241. Mongol armies on the western front, who had reached Hungary, turned back upon receiving news of the khan’s death, putting an end to the empire’s European conquests.

Mongke Khan

Mongke Khan (circa 1209–1259) assumed the khanate through a contested kuriltai. Sorqoqtani Beki, Mongke’s mother, had prepared diligently to give her four sons a chance to become Great Khan. Elite women played important roles in the empire, and after her husband Tolui died, Sorqoqtani rejected a marriage offer from Ogodei and managed to do so politely, realizing she would have more power if she remained independent. She made her move at the 1251 kuriltai, plotting with her nephew Batu to seat her eldest son, Mongke, on the throne over someone from Ogodei’s side of the family. The Ogodeids were furious but could not unite behind an alternative candidate. These maneuvers led to violent strife among Genghis Khan’s descendants.

Once Mongke came to power, he immediately ordered a purge of his Ogodeid opponents. These included the former regent Oghul Ghaimish, whom Mongke charged with witchcraft and had executed. Once he consolidated his power, Mongke carried out administrative reforms. He undertook a census of the whole empire to serve as a basis of complex tax and tribute policies, and he introduced coins and paper money to assist in tax collection. Mongke also put two of his brothers, Hulegu and Kublai, in charge of major military campaigns. Hulegu conquered Baghdad for the Mongols in 1258, executing the last leader of the Abbasid Caliphate. Kublai was stationed in northern China, fighting against the Song Dynasty in the south alongside Mongke himself, who was killed there in battle in 1259.

Kublai Khan

Kublai Khan (1215–1294) was in China when Mongke died. He and his brother Ariq Boke, who was based in Mongolia, were soon battling for the succession. Ariq Boke had support at home as a more traditional kind of steppe leader, but Kublai was able to leverage enough resources to prevail after four years of civil war between the brothers. Nevertheless, many considered his status as Great Khan of the Mongols to be suspect as he was not formally confirmed in a proper kuriltai. He also had a long-running armed conflict with his cousin Qaidu Khan, who controlled much of the Central Asian steppe.

Kublai faced political difficulties in China as well, ruling at the head of a foreign occupation. Yet he aspired to govern in the manner of a Chinese emperor. He built the city of Dadu (present-day Beijing) and moved the imperial capital there from Mongolia. He named his dynasty the Yuan, honoring the Chinese political tradition. He also restored China’s territorial unity when he captured the south from the Song Dynasty in 1279. Despite his efforts to adopt Chinese customs, he made sure to protect the interests of Mongols and keep them a separate, privileged class. Thanks to the famous travelogue written by the Venetian adventurer Marco Polo, the western world came to hear about the mighty Kublai Khan after his death.