Recently, I’ve been buttonholing everybody I know and telling them about Hulagu. What happened was, a couple of years ago Osama bin Laden said (in one of his intermittent recorded messages to the world) that during the previous Gulf War Colin Powell and Dick Cheney had destroyed Baghdad worse than Hulagu of the Mongols. Bin Laden provided no further identification of Hulagu, probably assuming that none was needed. Of course, almost no one in America had any idea what he was talking about, so news stories helpfully added that Hulagu, a grandson of Genghis Khan, was a Mongol general who sacked Baghdad in the year 1258. Beyond that footnote, the press as a whole shrugged at bin Laden’s out-of-left-field comparison and moved on.

At the time, I was doing research for a book about a subject in which the Mongols came up occasionally. Anyone who does research knows you have to stay focussed on your topic and not go down every interesting avenue you pass, or you will end up wandering aimlessly in attention-deficit limbo. I tried to keep on track, but whenever I spotted a reference to Hulagu, or descriptions of Mongol conquests in central Asia (Genghis Khan’s armies were said to have killed 1.6 million people in the city of Herat in northwestern Afghanistan in 1222; that’s 1.6 million, dispatched with arrows, clubs, and swords), the pointing finger of bin Laden kept distracting me. I wondered how a world figure like Hulagu could be so well known, apparently, in the far reaches of Asia, and the opposite of that here. I also wondered, in terms of simple fact, if it could be accurate to say that Cheney and Powell were worse than he. The cities in which Mongol history took place were often the same ones I’d seen in the newspaper that morning—Kabul, Qum, Kandahar, Mosul, Karbala, Tikrit. Reading about the Iraq war seemed to segue unavoidably into reading about the Mongols. Also, I have the possibly naïve belief that you should try to understand your enemy’s mind. Finally I quit resisting and went with the Mongol flow.

For the cities and cultivated places in the Mongols’ path, they were a natural disaster on the order of an asteroid collision. Like the Huns and the Scythians before them, they came from the steppe grasslands of central Asia, which produced their great resource of horses and draft animals. After Genghis Khan united a number of Mongol tribes into a single horde under his command in the early thirteenth century, they descended on cities in China, India, Afghanistan, Persia, Turkestan, and Russia. Between 1211 and 1223, they wasted dozens of cities and wiped out more than 18.4 million people in China and environs alone. (These and other large numbers of victims attributed to the Mongols may have been inspired more by terror than by historical fact.) By the time of Genghis Khan’s death, in 1227, the Mongol empire extended from the Volga River to the Pacific Ocean.

The Mongols had so many oxen and cattle that they were able to carry all kinds of stuff with them—entire houses, and even temples—on giant carts. Observers said the number of Mongol horses was beyond counting, every warrior possessing many remounts. Mongols spent so much time on horseback that they grew up bowlegged. If a Mongol had to move any distance farther than a hundred paces, he jumped on a horse and rode. A contemporary Russian annal describes the Mongol army approaching the walls of Kiev: “The rattling of their innumerable carts, the bellowing of camels and cattle, the neighing of horses, and the wild battle-cry, were so overwhelming as to render inaudible the conversation of the people inside the city.” Of necessity, the Mongols did most of their conquering and plundering during the warmer seasons, when there was sufficient grass for their herds.

Fuelled by grass, the Mongol empire could be described as solar-powered; it was an empire of the land. Later empires, such as the British, moved by ship and were wind-powered, empires of the sea. The American empire, if it is an empire, runs on oil and is an empire of the air. On the world’s largest landmass, Iraq is a main crossroads; most aspirants to empire eventually pass through there.

In battle, a historian wrote, “the Mongols made the fullest use of the terror inspired by their physique, their ugliness, and their stench.” Mongols were narrow-waisted and small-footed, with big heads. They shaved their hair short on the backs and tops of their heads and left it long at the sides. Custom forbade them from ever washing their clothes. Also contributing to their smell might have been their diet, which at certain times of the year was mainly mare’s milk. On marches when there wasn’t time to milk, Mongol riders would open a vein in their horses’ necks and drink the blood, either straight or from a pouch. Mongols were especially fond of fermented mare’s milk, called kumis. Many Mongol nobles died young from drunkenness. After victories, Mongols sometimes celebrated by drinking kumis while sitting on benches made of planks tied to the backs of their prisoners.

Mongols also ate meat tenderized by being sat on beneath their saddles on long journeys; marmot steeped in sour milk; curds dried in the sun; roots, dogs, rats—almost anything, according to several observers. Marco Polo, who travelled among them in the years 1275-92, wrote that they ate hamsters, which were plentiful on the steppes. A Franciscan friar who in 1245 went to seek out the Great Khan in the hope of persuading him to become a Christian reported that, during a siege of a Chinese city, a Mongol army ran out of food and ate one of every ten of its own soldiers. Mediterranean people who knew the Mongols only by reputation believed they were creatures with dogs’ heads who lived on human flesh.

Other Mongol facts: On their treeless steppes, they tended to get hit by lightning a lot. Thunder terrified them. They wore armor made of scales of iron sewn to garments of thick hide, and iron helmets that sometimes came to a point on top. Their swords were short and sometimes curved. The notches in their arrows were too narrow to fit the wider bowstrings of the Western people they fought, so that the arrows could not be picked up and shot back at them. Mongol bows, made of layers of horn and sinew on a wooden frame, took two men to string. Warriors carried them strung, in holsterlike cases at their belts. Mongols had no words for “right” and “left,” but called them “west” and “east,” respectively. When anyone begged from them, they replied, “Go, with God’s curse, for if he loved you as he loves me, he would have provided for you.”

Later commentators, trying to think of something positive to say about the Mongols, always mention that they were the first people to unite East and West, and to bring Europe and China real news of each other. The globally eye-opening books of Marco Polo would not have been possible without the safe passage provided for him by Mongol power. Mongols were curious about religions, and tolerant toward them. Mongol armies sometimes did not destroy churches, mosques, and monasteries. Eventually, many of the Mongol hordes combined their own shamanist beliefs with the Islam or Buddhism prevailing in the lands they overran. Unlike previous steppe barbarians, the Mongols had a strong body of laws, the yasaq, based on the decrees of Genghis Khan, and in many cases it remained in place for centuries in their conquered territories. In general, the Mongols were well organized. At their empire’s height, they had a fast and efficient postal service, of much greater extent than any the world had seen.