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.

By the fifteenth century, better defenses and the increased sophistication of firearms began to give civilized places an advantage over Mongol horsemen in warfare. The Mongols were becoming less dangerous, too, as they took up the domesticated customs of people they had ruled. Accompanying the Mongol empire’s eventual quiet retreat back into the steppes was the conversion of the majority of the Mongols to Tibetan Buddhism. Sonam Gyatso, who became the Dalai Lama in 1543, set out on a missionary journey to Mongolia in 1577, performed many miracles on the way, and was greeted by the Mongols with rejoicing. In less than a generation, many Mongols had become Lamaists, renouncing not only warfare but all other violence, including hunting and hawking. Today the Tibetan Buddhists believe that the saintly Sonam Gyatso is alive in his latest reincarnation, in the person of Tenzin Gyatso, the current Dalai Lama, recently seen smiling beatifically in ads for a computer brand.

During the time of Hulagu, the Mongols were still centuries from being peaceable. Hulagu—the name is also spelled Halagu, Hülegü, Hulégu, Khulagu, etc.—was the son of Genghis Khan’s son Tolui. Hulagu was the third-youngest among four brothers, all of them famous: Mongke, who outmaneuvered rivals to become khan in 1251, and who died of dysentery; Kubilai, arguably the most powerful khan ever, who occupied Peking and founded a Chinese dynasty that lasted almost a hundred years; Hulagu, an il-khan, or subsidiary khan, whose domains were in Persia and the west; and Arigh-boke, who rebelled against Kubilai and held out for years until Kubilai defeated him.

Because the Mongols absorbed many peoples and tolerated different religions, they soon had Buddhists, Muslims, Taoists, and even Christians among them. Hulagu was educated by a Nestorian Christian priest. Sorkhakhtani, Hulagu’s mother, was a Nestorian. (Nestorians held a less exalted view of the divinity of Christ, and were regarded by the Roman and Orthodox churches as heretics.) Hulagu’s principal wife, Dokuz-khatun, also a Nestorian, often persuaded Hulagu to be lenient toward Christians in lands that he conquered. Dokuz-khatun was said to be descended from one of the wise men who visited the baby Jesus in the manger. Hulagu seems never to have become a Christian himself, but members of the faith in the middle east saw him as their champion. Upon the death of this destroyer of multitudes, the head of the Jacobite Syriac Church said, “The wisdom of this man, and his greatness of soul, and his wonderful actions are incomparable. . . . Great sorrow came to all the Christians throughout the world.”

So on the one hand you’ve got Hulagu, and on the other you’ve got Baghdad. Mongols destroyed cities; Islam built them. In the years after the Prophet Muhammad’s death, in 632, his Arab followers spread their religion along the southern Mediterranean as far west as Spain and into central Asia as far east as Pakistan. Along the way, they founded new cities or enlarged old ones, and, of all the cities of early Islam, Baghdad became the wonder. The caliph—Islam’s spiritual leader, comparable to the Pope—founded it in 762 and finished its construction in 766. His name was Jaffar al-Mansour, and he belonged to the Abbassid line of caliphs, who descended from the Prophet’s paternal uncle, Abbas. The Abbassid caliphate lasted for five hundred years. Mansour chose the small village of Baghdad, on the Tigris, as the site for his future capital because of its possibilities for transportation and agriculture. He also liked its remoteness. He wanted to get away from the factional disputes that had come up in Islam’s previous capital cities of Medina, Damascus, Kufa, and Basra. Islam suffered from violent factions, notably the Sunni-Shia schism, dating from soon after Muhammad’s death. Mansour called his city Madinat as-Salaam, “the city of peace,” from a verse referring to Paradise in the Koran. The name Baghdad, however, prevailed.

Within forty years, Baghdad had become the storied and romantic place it would forever be in popular imagination. Under enlightened, poetry-loving caliphs like Harun al-Rashid, Mansour’s grandson, Baghdad attracted scholars from all the domains of Islam, in keeping with Muhammad’s teaching that educated men are next to the angels and that “the scholar’s ink is more sacred than the blood of martyrs.” Mansour’s prediction that his city would be a crossroads had come true, and wealth accumulated from caravan trade arriving from each of the four directions. Poets who pleased the caliph might have pearls poured upon them; concubines for his harem sold for tens of thousands of gold dirhams. A Chinese method for making paper from flax and hemp appeared in the Middle East at about the time of the city’s founding, and the new technology produced books in quantities impossible before. Almost everybody in ninth-century Baghdad could read and write. While Europe still moiled in its Dark Ages, Baghdad was a city of booksellers, bathhouses, gardens, game parks, libraries. Harun al-Rashid was the first chess-playing caliph; Baghdadis also played checkers and backgammon. Translators took Greek works and rendered them into Arabic, in which they were preserved to be translated into European languages several centuries later.

The palaces of the caliphs were of marble, rare woods, jade, and alabaster, with fountains and interior gardens, and carpets and wall hangings by the thousand. Servants sprinkled guests with sprinklers of rosewater and powdered musk and ambergris. A poet wrote, “Live long, O Caliph, to thy heart’s content / In scented shade of palace minarets.” Arts and sciences flourished—literature, music, calligraphy, philosophy, mathematics, chemistry, history. Because of the need for accuracy in setting the religious calendar and orienting mosques to face Mecca, astronomy was especially important. From Baghdad’s best years we get words like “zenith” and “nadir,” as well as “algebra,” “algorithm,” “alcohol,” “alembic,” “alchemy.” The food in Baghdad was great, too, apparently. The city’s gardens grew a cornucopia of fruits, spices, pistachios, licorice root. Its cooks knew how to make highly complicated dishes, and sweets like halvah and baklava.

As happens with most golden eras, Baghdad’s quickly ended. A century after Harun al-Rashid, the city’s influence and glory had declined. Political changes made the caliph less powerful, limiting his temporal domain to Baghdad and nearest regions, though Sunni Muslims in other places still accepted his spiritual authority. The city remained a center of wealth and commerce, and an imposing sight architecturally. A Spanish pilgrim, Ibn Jubayr, who visited Baghdad in 1184, wrote, “The Tigris . . . runs between its eastern and its western parts . . . like a string of pearls between two breasts.” He noted the beauty of the caliph’s palace reflected in the water. Caliph Mustasim, the thirty-seventh in the Abbassid line, who became caliph in 1242, had confidence that his house would reign until Resurrection Day. Rumors of the approach of the Mongol army in 1257 did not worry him. During the reign of his father, the armies of the caliph had been among a very few opponents to defeat and turn back the Mongols.

From deep in Mongolia Hulagu set out in 1253, marching westward at the head of a large force that included siege-engine experts of several nationalities. His trebuchets could hurl huge rocks, and smaller stones covered in flaming naphtha, and his arbalesters could shoot bolts dipped in burning pitch a distance of twenty-five hundred paces. Hulagu’s brother Mongke Khan told him to subdue the people he encountered as he continued all the way to Egypt, being kind to those who submitted and killing or enslaving the rest. The Mongols took eighteen months crossing Asia as far as Afghanistan. There and in the mountains of Persia they stopped to conquer the Assassins, an extreme Shiite sect that terrorized neighboring rulers by sending young men on suicide missions to kill them. The young men were drugged with hashish (source of the word “assassin”) and were told that when they died they would immediately go to Paradise, where women and other pleasures awaited. In no-quarter sieges, Hulagu battered the Assassins out of their mountain fortresses with his heavy weapons, and then destroyed them root and branch. Later historians agreed that in this, at least, he did the world a favor.

By 1257, Hulagu had reached western Persia. From there he sent emissaries to the caliph telling him to raze the walls of Baghdad and fill in the moat and come in person to make obeisance to Hulagu. The caliph replied that with all of Islam ready to defend him, he did not fear. He advised Hulagu to go back where he came from. The Mongol army had recently received reinforcements from other Mongol hordes, and a contingent of Christian cavalry from Georgia. Perhaps the Mongols had eight hundred and fifty thousand soldiers; certainly they had more than a hundred thousand. In November of 1257, they marched on toward Baghdad, dividing as they approached so that their forces would surround the city. The caliph sent an army to stop those approaching from the west, and repulsed them in an early battle. In the next encounter, the Mongols broke some dikes and flooded the ground behind the caliph’s army, and slaughtered or drowned them all.

Mustasim, the caliph, was not of a character equal to such large problems. He is described as a weak, vacillating layabout who liked to drink sherbet and keep company with musicians and clowns. Worse, from a strategic point of view, Mustasim had recently angered the Shiites by various insults and offenses, such as throwing the poem of a famous Shiite poet in the river. Now vengeful Shiites volunteered help to the Mongols in Mosul and other places along their march. The caliph’s vizier, or chief minister, was himself a Shiite of uncertain loyalty. Islamic opinion afterward held that the vizier, al-Alkamzi, vilely betrayed the caliph and conspired with the Mongols; an exhortation in Muslim school books used to say, “Let him be cursed of God who curses not al-Alkamzi.” As fighting began, Hulagu, acknowledging the importance of Shiite support, prudently posted guard detachments of a hundred Mongol horsemen at the most sacred Shiite shrines in Najef and Karbala.

On January 29, 1258, Hulagu’s forces took up a position on the eastern outskirts of Baghdad and began a bombardment. Soon they had breached the outer wall. The caliph, who had been advised against escaping by his vizier, offered to negotiate. Hulagu, with the city practically in his hands, refused. The upshot was that the caliph and his retinue came out of the city, the remainder of his army followed, they laid down their arms, and the Mongols killed almost everybody. Hulagu told Baghdad’s Christians to stay in a church, which he put off-limits to his soldiers. Then, for a period of seven days, the Mongols sacked the city, killing (depending on the source) two hundred thousand, or eight hundred thousand, or more than a million. The Mongols’ Georgian Christian allies were said to have particularly distinguished themselves in slaughter. Plunderers threw away their swords and filled their scabbards with gold. Silver and jewels and gold piled up in great heaps around Hulagu’s tent. Fire consumed the caliph’s palace, and the smoke from its beams of aloe wood, sandalwood, and ebony filled the air with fragrance for a distance of a hundred li. (A li equalled five hundred bow lengths—a hundred li was maybe thirty miles.) So many books from Baghdad’s libraries were flung into the Tigris that a horse could walk across on them. The river ran black with scholars’ ink and red with the blood of martyrs.

The stories of what Hulagu did to the caliph vary. One says that Hulagu toyed with him a while, dining with him and discussing theology and pretending to be his guest. A famous account describes how Hulagu imprisoned the caliph in a roomful of treasure and brought him gold on a tray instead of food. The caliph protested that he could not eat gold, and Hulagu asked him why he hadn’t used his money to strengthen his army and defend against the Mongols. The caliph said, “That was the will of God.” Hulagu replied, “What will happen to you is the will of God, also,” leaving him among the treasure to starve.