Genghis Khan, ruler of the Mongol Empire, the largest contiguous empire the world has ever seen, died on August 18th, 1227, aged about 65. Known in his youth as Temujin, he united various nomadic tribes and launched them on a campaign of conquest that stretch from the Pacific, across Asia and into Europe.
Unlike the Romans, who sought to incorporate conquered peoples into their domain, Genghis Khan’s Mongols practised mass slaughter of local populations, and he was feared for the brutality he practised himself and encouraged among his followers. In his 2009 Military History of Iran, Steven R. Ward wrote that "Overall, the Mongol violence and depredations killed up to three-fourths of the population of the Iranian Plateau, possibly 10 to 15 million people." Iran's population did not again reach its pre-Mongol levels until the mid-20th Century. Over the course of three years, the Mongols annihilated nearly all of the major cities of Eastern Europe. Kiev, once thickly populated was reduced to a couple of hundred households kept in slavery, such that the Pope's envoy wrote, "We came across countless skulls and bones of dead men lying about on the ground."
China's population declined dramatically, with the population of north China falling from an estimated 50 million in 1195 to 8.5 million in the Mongol census of 1235–36, and it was a similar story elsewhere in the Mongol conquests. Although Genghis Khan is sometimes hailed as a military leader and political genius, exalted in art and gloried in literature, he is more accurately viewed as a brutal tyrant who brought together a war machine that was superior to any that could be set against him.
Conquerors such as Augustus Caesar and his successors brought commerce, trade and the trappings of civilization to the peoples they subdued and absorbed, but Genghis Khan seems to have brought little but bloodshed. It was his grandson, Kublai Khan, who completed the unification of China and established a dynasty that enabled a long period of peace and commerce. Genghis Khan left his mark in other ways. His name is still reviled among many descendants of the people he butchered. He was also prolific in using his power to satisfy his personal desires, as most tyrants do. A 2003 study found there are about 16 million men alive today who carry his DNA.
History has long been taught as the story of conquerors and empires. Edward Gibbon wrote of the emperor, Antoninus Pius, "The reign of Antoninus is marked by the rare advantage of furnishing very few materials for history, which is indeed little more than the register of the crimes, follies, and misfortunes of mankind."
Karl Popper wrote in his 1945, "The Open Society and its Enemies’:
There is no history of mankind, there is only an indefinite number of histories of all kinds of aspects of human life. And one of these is the history of political power. This is elevated into the history of the world. But this, I hold, is an offence against every decent conception of mankind. It is hardly better than to treat the history of embezzlement or of robbery or of poisoning as the history of mankind. For the history of power politics is nothing but the history of international crime and mass murder (including it is true, some of the attempts to suppress them). This history is taught in schools, and some of the greatest criminals are extolled as heroes.
Genghis Khan did indeed have a great influence on the world, as did Napoleon, as did Hitler, but it is one to be deplored, rather than lauded.