The Mongol Empire: Genghis Khan, his heirs and the founding of modern China

by John Man

  In Chinese eyes, Genghis and Kublai and all their conquests were actually Chinese.

  And so therefore is Tibet.

  fn1 In Rossabi (ed.), China among Equals (see Bibliography).

  fn2 That was his title, by which he is usually known. His name was Günga Gyaicain, and he is still revered as one of the supreme Buddhist scholars.

  fn3 The ‘s’ is silent now. Back then, it was sounded. At a conference in China in 2012, a Tibetologist scolded me for pronouncing it. Transcribing Tibetan is a minefield.

  fn4 In the Service of the Khan (see Bibliography).

  fn5

  17

  THE CONQUEST OF THE SOUTH

  SOME THINGS ARE non-negotiable. For Kublai, conquest of Song was one of them. He had tried once, and failed. Like his grandfather, Kublai was not to be put off by failure. He returned to the task in 1268, after crushing Li Tan’s rebellion. It was a formidable challenge. Song was all rivers and cities, exactly what Mongolia and most of north China wasn’t. Cities were the prizes, because that was where the rich lived and the powerful administered – there were no castles such as the European and Japanese nobility had. As a result, cities were tough nuts, well supplied with explosives, many of them on rivers, the better to trade and feed themselves. The Mongols needed not only even better ways to take cities, but also something new – a navy of river boats, which would have to be started from scratch.

  The key was the mighty Yangtze, beyond whose lower reaches lay the capital, Hangzhou. Any advance therefore had to be by river. The Yangtze flows from west to east, while Kublai’s armies would be invading from the north. But right in the middle of the Mongol–Song border a major tributary, the Han, ran southwards, making a river-road straight down to the lower Yangtze – and Hangzhou.

  There was just one problem. The Han had its own key, in the form of the town of Xiangyang,fn1 which lies on the Han at the junction of two other rivers, 250 kilometres north of the Yangtze. Today, Xiangyang and its sister-city across the river, Fancheng, form the super-city of Xiangfan. In Kublai’s day, Xiangyang was a moated fortress-city and a major trade crossroads, with a population of 200,000 people, linked to Fancheng by a pontoon bridge. Xiangyang would have to be eliminated by any army heading south by river.

  This was common knowledge on both sides, because the city had been a prime target twice before – in a Jin assault in 1206–7 and in Ogedei’s 1235–41 campaign. It had not fallen either time, but surrendered in 1236 to the Mongols, who held it only briefly, before returning north. So Xiangyang was used to taking punishment and had been busy rebuilding its defences. It had 6 kilometres of solid stone walls, some 6–7 metres high, set in a rough square just over a kilometre across; three of the six gates gave directly on to the river, which was a highroad for supplies and communication half a kilometre wide when it was in flood, and far too deep to wade; in winter, when the water was low, it became a maze of frozen channels and sandbars; and the moat, fed from the river, was 90 metres across; all of which meant that attackers could not get close enough either to assault the walls with ladders and towers or to undermine them.

  This chapter is largely about the solution to this problem, which when solved led on to Kublai’s greatest achievement: the creation of a unified China and the establishment of borders that are largely still in place today. The evidence is patchy, but still good enough to conclude that modern China owes its existence to the device that broke the siege of Xiangyang – a device such as China had never seen before.

  It began with Mongols approaching the city in early 1268, under the command of the young and famous Aju – famous because military glory was in the family. He was the son of Uriyang-khadai, who had won Yunnan for Kublai ten years before, and the grandson of the legendary Subedei, who had masterminded Genghis’s and Mönkhe’s western campaigns. Almost as soon as he started his advance, Aju found he needed help, in the form of infantry – and boats, a novelty for the Mongols, built by a Song defector named Liu Zheng. Kublai complied, giving Aju the amphibious force he needed for an advance by river and by land.

  Aju and his army would not have found much in the way of loot to sustain them, because in preparation for a siege city rulers customarily ordered a scorched-earth policy, clearing the surrounding countryside of anything that might help the enemy: high buildings, trees, stones, metals, tiles, vegetables, straw, animals, grain. Much of this went into the city,fn2 where there was work to be done: stores to be gathered, civilians trained as militiamen, women organized in cooking gangs, itinerant entertainers expelled as potential spies, fire brigades equipped with water jars, double and triple crossbows made ready, trebuchets checked.

  Trebuchets are a major theme in this chapter. The backbone of Chinese siege technology was the ‘traction trebuchet’, a frame about 4 metres high on which pivoted an 11–12-metre pole, with a sling on one end and ropes on the other. A small rock or incendiary device was loaded in the sling, a team hauled on the other end, the sling whipped round and released the missile. The whole operation took no more than 15 seconds. For lobbing rocks over walls, the traction trebuchet was standard technology. Any army would muster scores, sometimes hundreds of teams, working in relays. They needed their own food, armour and horses. Before a siege, defenders gathered huge quantities of stone from surrounding areas, for their own use and to deprive the opposition of ammunition. Defending trebuchet teams would work in relative safety from inside the walls, with an artillery-spotter up above to direct them.

  This precursor to the cannon, acquired by the Mongols from the Chinese, was both a biological weapon and a shotgun. Its bamboo barrel fired a combination of poison and shards of porcelain. Its label (top right) reads ‘sky-filling spurting tube’.

  Trebuchets had one huge disadvantage, though, especially for the defenders. If they used rocks, the cheapest ammunition, they simply supplied ammunition to the other side. The same rocks arced back and forth over the walls, shattering heads, breaking arms, smashing roofs, on occasion in such numbers that the missiles crashed together in mid-air. Whether in defence or attack, 100 devices could deliver up to 12,000 rocks per hour, hour after hour, day after day. Where would all the ammunition come from? How many men and horses would it take to find it, cut it, transport it? The challenge was an incentive to develop more effective projectiles.

  All Chinese armies employed experts in explosive devices and chemical warfare. The techniques, based on some 700 years of experimentation by alchemists, had been developed from the first use of gunpowder in war in the early tenth century. Rapidly, a whole range of gunpowder-based weapons had appeared: exploding arrows, mines, and bombs thrown by trebuchets. One of these consisted of gunpowder packed into bamboo and surrounded by broken porcelain, the first known use of shrapnel. Another was the much more deadly ‘thunder-crash bomb’, which detonated inside a metal casing, blasting to bits anything within about 400 square metres. The exploding poison devices, the first steps in chemical and germ warfare, included the original dirty weapon, a bomb filled with excrement and poisonous beetles.

  When the siege of Xiangyang began early in 1268, these weapons brought Aju’s advance to a halt. The war developed into a five-year epic, a sort of Chinese Trojan War. Unfortunately, no local Homer spun the siege into epic verses, so details are few, until the climax.

  A proper blockade required yet more boats, 500 of them, built under the supervision of Kublai’s admiral, Liu Zheng. The construction took months. Through the summer, the Mongols erected fortifications downriver on either bank to bombard Song boats ferrying in supplies. As winter came on again, Aju extended the siege across the river to include Fancheng. An attempt by the Chinese to break out ended in disaster for them: hundreds were captured and beheaded. After that, the Chinese sat tight, with enough supplies reaching them to survive. In spring 1269, Kublai sent in another 20,000 troops to strengthen the besiegers. In August, after eighteen months of action and inaction, 3,000 Song boats came up the Han to attack the new Mongol fortifications and were r
epulsed with the loss of 2,000 men and fifty boats. Kublai’s commanders requested another 70,000 troops and more boats. The Chinese defenders, reassured by secret-service officers smuggling in orders, cash and letters sealed inside balls of wax, were equally determined to resist.

  What could break the stalemate? As a Mongol general told Kublai, the army needed better artillery. The Mongols already had artillery of many kinds – mangonels, trebuchets, arrow-firing ballistas – having acquired the technology and specialist troops after the siege of Beijing in 1215. The problems were Xiangyang’s moat and stone walls. The Mongol–Chinese artillery simply didn’t have the range or the power.

  Kublai, hearing of the problem, also saw the solution: a siege engine such as China had never seen before. He knew that the empire’s best siege-engine designers were in Persia, 6,000 kilometres away, because he had seen reports of the siege of Baghdad by his brother Hulegu in 1258. Hulegu had catapults that breached walls. Traction trebuchets could not do that. Hulegu’s machines were of a different order.

  They were counterweight trebuchets, the heavy artillery of their day, in which men pulling on ropes were replaced by a box filled with ballast (usually rocks), the advantage being that the weight could be enormous, the throwing arm lengthened, the missile heavier, the sling extended, the range increased and accuracy improved.

  The counterweight trebuchet had emerged in the Middle East in the twelfth century, spreading to Europe soon after crusading armies came across them in about 1200. Information flowed both ways, the machines developing in both Europe and the Islamic world into specialized devices that not only destroyed walls but seized imaginations, influenced strategy and made stars of their engineers (who therefore had a good reason never to record their secrets). By the end of the fifteenth century, they were gone, blown away by gunpowder. They were only wood, after all.

  Today there is an international subculture of ‘treb’ enthusiasts who have worked out the secrets of these giant machines. Combining theoretical science, history and practicality, they are keenly, many obsessively and some eccentrically dedicated to the business of hurling huge loads as far as possible without the use of explosives. In the 1990s, a 30-tonne trebuchet threw half a dozen cars, sixty pianos and many dead pigs, earning a good deal of notoriety. Websites speak of plans for Thor, with a 100-foot arm and a 25-tonne counterweight, which will supposedly toss Buicks as the war god tossed thunderbolts. At the time of writing, Thor was still a dream.

  I can understand the passions they arouse. On a visit to Caerphilly Castle, South Wales, I got to use one. There is beauty in what happens when this pent-up energy is released, because it involves only natural elements – wood, iron, rock, rope, gravity – carefully managed. A jerk on the trigger frees the arm. The counterweight drops, the arm rises, the sling follows with its missile. The only sounds are soft, like a giant exhalation: a whisper from the greased axle, the swish of the sling. It’s all in slow motion, rather graceful. Away the missile flies, in this case landing harmlessly in a field. Then the great beast resettles with little sounds of satisfaction – sighs from the counterweight swinging back and forth, the clunk of heavy stones rearranging themselves inside, the slap of the empty sling against the waving lever-arm.

  So we know what Kublai was after. He knew it was possible. It was just a question of joining the dots. Nothing could have better shown the advantages of having an empire all run by one family, bound together by a network of transcontinental communications. Off went Kublai’s letter by pony express. Five weeks later and 6,000 kilometres away, his message was in Tabriz, northern Persia, HQ of his nephew Abaqa, Persia’s ruler since the death of his father, Hulegu, in 1265. Abaqa had on hand several engineers who had built the counterweight trebuchets used in many sieges: Baghdad, Aleppo, Damascus, Syria’s crusader castles. He could spare two of them, Ismail and Ala al-Din. In late 1271, the two arrived with their families at Xanadu and were given an official residence for the winter. The following spring, after demonstrating the principles to the emperor, the two men – plus Ismail’s son, whom he was training to follow in his footsteps – found themselves in the battle zone, staring at Xiangyang’s solid walls, the moat, the broad river and Fancheng, Xiangyang’s sibling city across the river.

  Ismail’s machine, probably built on site, must have weighed 40 tonnes and towered almost 20 metres high. There were many variables, like the exact weight of the counterweight in wet and dry weather, the effect of temperature on the grease used on wooden axles in wooden bearings, the right timber to use for the lever-arm, the shape of the 100-kilo missiles, which were hacked from a local quarry.

  The Mongol general Ariq Khaya decided on an indirect approach by assaulting Fancheng. After destroying the pontoon bridge to prevent supplies being carried across, Ismail would have fine-tuned his device like an artilleryman, with ranging shots. Then, as Ariq Khaya’s biography in the Yuan Shi says, Ismail’s hui-hui pao (Muslim catapult) ‘breached the walls . . . [since] the reinforcements from Xiangyang no longer reached the fortress, it was captured’.

  That created a situation the Mongols had often faced. To force Xiangyang to surrender, Fancheng had to die, very publicly. Some 3,000 soldiers and an estimated 7,000 others had their throats cut like cattle, the bodies being piled up in a mound to make sure that the massacre was visible from Xiangyang.

  But there was no surrender. So Ismail turned his siege engine on Xiangyang, dismantling it, floating it across the river, reassembling it within range of Xiangyang, ‘at the south-east corner of the city’, according to the Yuan Shi. Ismail, a master of his art, now knew his machine’s abilities very precisely. The missile, we are told, weighed 150 catties, which is just short of 100 kilos. The result was astonishing. In the words of Ariq Khaya’s biography, ‘The first shot hit the watch-tower. The noise shook the whole city like a clap of thunder, and everything inside the city was in utter confusion.’

  There then followed a debate about whether to follow through with an assault, which would, of course, end with another pile of bodies, but with rather less strategic purpose. Ariq Khaya had his own ideas. He went in person to the foot of the wall and called for the city’s leader, Lü Wenhuan. ‘You have held the city with an isolated army for many years,’ he shouted (presumably through an interpreter). ‘But now the approaches are cut off even from the birds of the air. My master the emperor greatly admires your loyalty and if you surrender he will give you an honourable post and a generous reward. You may be sure of this, and we certainly shall not kill you.’

  Lü, ‘suspicious as a fox’, hesitated briefly, finally believed the assurances, and surrendered the city on 17 March 1273. Ariq Khaya was as good as his word. Lü instantly made himself a traitor in Song eyes and accepted high office on Kublai’s side. He would prove a valuable asset in the coming campaign.

  It is hard to overstate the significance of this victory.fn3 Not only did it open the way militarily to Song’s heartland, but it began to destroy the workings of Song government. In Hangzhou, the prime minister, Jia Sidao – Kublai’s old adversary, the rich politician who liked crickets and their pugnacious ways – had kept the truth from the Song emperor, so the news of Xiangyang’s fall struck the court like a ball from a Muslim catapult.

  A grateful Kublai rewarded both catapult experts. Ala al-Din became an overseer, a top local official, serving the Yuan for the next thirty years. Ismail was given some 9 kilos of silver, about ten years’ income for an artisan. He had no time to enjoy it, because a year later he fell ill and died. His work, though, lived on. His position and expertise were inherited by his son, Abu-Bakr, beginning a line of succession that would continue almost until the end of the Yuan dynasty.

  In Hangzhou, panic took hold. Suddenly, top people woke up to the threat to their comfortable and civilized ways, their literate discourses, their picnics by the West Lake, their time-honoured rituals, their glorious works of art. It was unthinkable – never before in China’s history had barbarians threatened the southern heartland
.

  And then catastrophe upon catastrophe. Without warning, the Emperor Duzong died, at only thirty-four. Next, the Mountain of Heavenly Visage, the beautiful volcanic range a day’s ride west of Hangzhou, shook itself and released devastating landslides and flood waters. It was a dire omen, because in Chinese a landslide and an imperial death are different meanings of the same character, bēng . Disasters were linking up, like tears in old silk, and there was no one to patch Song’s tattered fabric. Heaven was withdrawing its mandate to rule. An age approached its end.

  For this vast and vital campaign, Kublai wanted to leave no room for error. He retained Aju, the victor of the Xiangyang siege, but placed him under his dynamic and widely experienced statesman-general, Bayan. He was from a legendary family. His great-grandfather, grandfather and great-uncle had been the three who, sixty years before, had spared the life of Genghis’s enemy, Targutai, and been rewarded by Genghis for their loyalty. Bayan’s father had been with Hulegu in 1256 and died in action. Bayan had joined Kublai as one of his top civilian administrators. He had a reputation for calmness under pressure and for brilliance (he had learned Chinese). At the age of only thirty-four, he found himself with the task of taking one more giant step towards world conquest.

  The advance down the Yangtze was to be an immense operation. The army that Bayan and Aju gathered around Xiangyang in summer 1274 numbered about 200,000 infantrymen, over half of them northern Chinese, backed by a river fleet of 800 newly built warships and another 5,000 smaller boats for transport, carrying 70,000 sailors, 14 per boat. This was a flexible, amphibious, multinational force. It needed to be, because the Song still had 700,000 men at their disposal and 1,000 warships on the Yangtze.