Genghis Khan

Yesügei's death shattered the unity of his people. As Temüjin was only around ten, and Behter around two years older, neither was considered old enough to rule. Led by the widows of Ambaghai, a previous Mongol khan, a Tayichiud faction excluded Hö'elün from the ancestor worship ceremonies which followed a ruler's death and soon abandoned the camp. The Secret History relates that the entire Borjigin clan followed, despite Hö'elün's attempts to shame them into staying with her family.[30] Rashid al-Din and the Shengwu qinzheng lu however imply that Yesügei's brothers stood by the widow. It is possible that Hö'elün may have refused to join in levirate marriage with one, or that the author of the Secret History dramatised the situation.[31] All the sources agree that most of Yesügei's people renounced his family in favour of the Tayichiuds and that Hö'elün's family were reduced to a much harsher life.[32] Taking up a traditional hunter-gatherer lifestyle, they collected roots and nuts, hunted for small animals, and caught fish.[33]

Tensions developed as the children grew older. Both Temüjin and Behter had claims to be their father's heir: although Temüjin was the child of Yesügei's chief wife, Behter was at least two years his senior. There was even the possibility that, as permitted under levirate law, Behter could marry Hö'elün upon attaining his majority and become Temüjin's stepfather.[34] As the friction, excarbated by regular disputes over the division of hunting spoils, intensified, Temüjin and his younger brother Qasar ambushed and killed Behter. This taboo act was omitted from the official chronicles but not from the Secret History, which recounts that Hö'elün angrily reprimanded her sons. Behter's younger full-brother Belgutei did not seek vengeance, and became one of Temüjin's highest-ranking followers alongside Qasar.[35] Around this time, Temüjin developed a close friendship with Jamukha, another boy of aristocratic descent; the Secret History notes that they exchanged knucklebones and arrows as gifts and swore the anda pact—the traditional oath of Mongol blood brothers–at the age of eleven.[36]

As the family lacked allies, Temüjin was likely taken prisoner on multiple occasions.[37] The Secret History relates one such occasion when he was captured by the Tayichiuds who had abandoned him after his father's death. Escaping during a Tayichiud feast, he hid first in the River Onon and then in the tent of Sorkan-Shira, a man who had seen him in the river and not raised the alarm; Sorkan-Shira sheltered Temüjin for three days at great personal risk before allowing him to escape.[38] Temüjin was assisted on another occasion by an adolescent named Bo'orchu who aided him in retrieving stolen horses. Soon afterwards, Bo'orchu joined Temüjin's camp as his first nökor (personal companion; PL nökod).[39] These incidents are indicative of the emphasis the author of Secret History put on personal charisma.[40]

Burkhan Khaldun mountain, where Temüjin hid during the Merkit attack, and which he later came to honour as sacred

Accompanied by Belgutei, Temüjin returned to Dei Sechen to marry Börte when he became an adult at fifteen. The Onggirat chieftain, delighted to see the son-in-law he feared had been lost, immediately consented to the marriage, and accompanied the newlyweds back to Temüjin's camp; his wife Čotan presented Hö'elün with a black sable cloak, a sign of great wealth.[41] Seeking a patron, he then chose to approach Toghrul, khan of the Kerait tribe, who had fought alongside Yesügei and sworn the anda pact with him. Toghrul ruled hundreds of miles and commanded up to 20,000 warriors, but he was suspicious of the loyalty of his chief followers and, after being presented with the sable cloak, he welcomed Temüjin into his protection. The two grew close, and Temüjin began to build a following, as nökod such as Jelme entered into his service.[42]

Soon afterwards, seeking revenge for Yesügei's abduction of Hö'elün, around 300 Merkits raided Temüjin's camp. While Temüjin and his brothers were able to hide on Burkhan Khaldun, Börte and Sochigel were abducted. In accordance with levirate law, Börte was given to Chilger, younger brother of Chiledu.[43] Temüjin appealed for aid from Toghrul and his childhood anda Jamukha, who had risen to become chief of the Jadaran tribe. Both chiefs were willing to field armies of 20,000 warriors, and with Jamukha in command, the campaign was soon won. A now-pregnant Börte was recovered successfully and soon gave birth to a son, Jochi; although Temüjin raised him as his own, questions over his true paternity followed Jochi throughout his life.[44] This is narrated in the Secret History and contrasts with Rashid al-Din's account, which protects the family's reputation by removing any hint of illegitimacy.[45]

Temüjin and Jamukha camped together for a year and a half, during which, according to the Secret History, they reforged their anda pact, even sleeping together under one blanket. Traditionally seen as a bond solely of friendship, as presented in the source, Ratchnevsky has questioned if Temüjin was actually serving as Jamukha's nökor, in return for the assistance with the Merkits.[46] Tensions arose and the two leaders parted, ostensibly on account of a cryptic remark made by Jamukha on the subject of camping; scholarly analysis has focused on the active role of Börte in this separation, and whether her ambitions may have outweighed Temüjin's own. In any case, the major tribal rulers remained with Jamukha, but forty-one named leaders joined Temüjin along with many commoners: these included Subutai and others of the Uriankhai, the Barulas, the Olkhonuds, and many more.[47]

Temüjin and Toghrul, illustrated in a 15th-century Jami' al-tawarikh manuscript

Temüjin was soon acclaimed by his close followers as khan of the Mongols.[48] Toghrul was pleased at his vassal's elevation but Jamukha was resentful. Tensions escalated into open hostility, and in around 1187 the two leaders clashed in battle at Dalan Baljut: the two forces were evenly matched but Temüjin suffered a clear defeat. Later chroniclers including Rashid al-Din instead state that he was victorious but their accounts contradict themselves and each other.[49]

Modern historians such as Ratchnevsky and Timothy May consider it very likely that Temüjin spent a large portion of the decade following the clash at Dalan Baljut as a servant of the Jurchen Jin dynasty.[50] Zhao Hong, a 1221 ambassador from the Song dynasty, recorded that the future Genghis Khan spent several years as a slave of the Jin. Traditionally seen as an expression of Song arrogance, the statement is now thought to be based in fact, especially as no other source convincingly explains Temüjin's activities between Dalan Baljut and c. 1195.[51] Taking refuge across the border was a common practice both for disaffected steppe leaders and disgraced Chinese officials. Temüjin's reemergence c. 1195 having retained significant power indicates that he probably profited in the service of the Jin. As he would later go on to overthrow that state, such an episode, detrimental to Mongol prestige, was omitted from all their sources. Zhao Hong was bound by no such taboos.[52]

The Serven Khallga inscription, which commemorates the 1196 campaign against the Tatars

The sources do not agree on the events of Temüjin's return to the steppe. In early summer 1196, he participated in a joint campaign with the Jin against the Tatars, who had begun to exert their power. As a reward, the Jin awarded him the honorific cha-ut kuri. At around the same time, he assisted Toghrul with reclaiming the lordship of the Kereit, which had been taken by a family member with the support of the powerful Naiman tribe.[53] Toghrul was given the title of Ong Khan by the Jin, traditionally as a reward for his support during the Tatar campaign. In fact, Toghrul may not have participated in the warfare, and the title was only thus given as a pacificatory gesture. In all versions of events, the actions of 1196 fundamentally changed Temüjin's position in the steppe—he was now Toghrul's equal ally, rather than his junior vassal.[54]

Jamukha had behaved poorly following his victory at Dalan Baljut, allegedly beheading enemy leaders and humiliating their corpses, or boiling seventy prisoners alive. A number of disaffected followers, including Yesügei's nökor Münglig and his sons, defected to Temüjin as a consequence.[55] Temüjin was able to subdue the disobedient Jurkin tribe that had previously offended him at a feast and refused to participate in the Tatar campaign. After eliminating their leaders, he had Belgutei symbolically break a leading Jurkin's back in a staged wrestling match in retribution. This latter incident, which contravened Mongol customs of justice, was only noted by the author of the Secret History, who openly disapproved. These events occurred c. 1197.[56]

The tribal polities united by Temüjin to found the Mongol Empire

During the following years, Temüjin and Toghrul campaigned separately and together against the Merkits, the Naimans, and the Tatars. In around 1201, a collection of dissatisfied tribes including the Onggirat, the Tayichiud, and the Tatars, swore to break the domination of the Borjigin-Kereit alliance, electing Jamukha as gurkhan and their leader. After some initial successes, this loose confederation was routed at Yedi Qunan, and Jamukha was forced to beg for Toghrul's clemency.[57] Desiring complete supremacy in eastern Mongolia, Temüjin defeated first the Tayichiud and then, in 1202, the Tatars; after both campaigns, he executed the clan leaders and took the remaining warriors into his service. These included Sorkan-Shira, who had come to his aid previously, and a young warrior named Jebe, who, by killing Temüjin's horse and refusing to hide that fact, had displayed military skill and personal courage.[58]

The absorption of the Tatars left three military powers in the steppe: the Naimans in the west, the Mongols in the east, and the Kereit in between.[59] Seeking to cement his position, Temüjin proposed that his son Jochi marry one of Toghrul's daughters. Led by Toghrul's son Senggum, the Kereit elite believed the proposal to be an attempt to gain control over their tribe, while the doubts over Jochi's parentage would have offended them further. In addition, Jamukha drew attention to the threat Temüjin posed to the traditional steppe aristocracy. Yielding eventually to these demands, Toghrul attempted to lure his vassal into an ambush, but his plans were overheard by two herdsmen. Temüjin was able to gather some of his forces, but was soundly defeated at the Battle of Qalaqaljid Sands.[60]

Temüjin retreated southeast to Baljuna, an unidentified lake or river, where he waited for his scattered forces to regroup: Bo'orchu had lost his horse and was forced to flee on foot, while Temüjin's badly wounded son Ögedei had been transported and tended to by Borokhula, a leading warrior. He called in every possible ally and swore a famous oath of loyalty, later known as the Baljuna Covenant, to his faithful followers, which would later grant them exclusivity and prestige.[62] The oath-takers of Baljuna were a very heterogenous group—men from nine different tribes, who included Christians, Muslims, and Buddhists united only by loyalty to Temüjin and to each other; this group became a model for the later empire, being termed a "proto-government of a proto-nation" by historian John Man.[63] The Baljuna Covenant was omitted from the Secret History—as the group was predominantly non-Mongol, the author presumably wished to downplay the role of other tribes.[64]

A ruse de guerre involving Qasar allowed the Mongols to catch the Kereit unawares at the Jej'er Heights, but though the ensuing battle still lasted three days, it ended in a decisive victory for Temüjin. Toghrul and Senggum were both forced to flee, and while the latter escaped to Tibet, Toghrul was killed by a Naiman who did not recognise him. Temüjin sealed his victory by absorbing the Kereit elite into his own tribe: he took the princess Ibaqa to be his own wife, and gave her sister Sorghaghtani and niece Doquz to his youngest son Tolui.[65] The ranks of the Naimans had swelled due to the arrival of Jamukha and others defeated by the Mongols, and they soon prepared for war. Temüjin was informed of these events by Alaqush, the sympathetic ruler of the Ongud tribe. In the Battle of Chakirmaut, which occurred in May 1204 in the Altai Mountains, the Naimans were decisively defeated: their leader Tayang Khan was killed, and his son Kuchlug was forced to flee west.[66] The Merkits were decimated later that year, while Jamukha, who had abandoned the Naimans at Chakirmaut, was betrayed to Temüjin by companions who were executed for their lack of loyalty. According to the Secret History, Jamukha convinced his childhood anda to execute him honourably; other accounts state that he was killed by dismemberment.[67]

Temüjin being proclaimed as Genghis Khan, as illustrated in a 15th-century Jami' al-tawarikh manuscript. The tuq banner, composed of yak or horse tails, is placed on the right; its white colour represented peace, while a black tuq meant war.[68]

Now sole ruler in the steppe, Temüjin held a kurultai at the source of the Onon River in 1206.[69] Here, he formally adopted the title Genghis Khan, the etymology and meaning of which has been much debated. Some commentators hold that the title had no meaning, simply representing Temüjin's eschewment of the traditional "gurkhan" title, which had been accorded to Jamukha and was thus of lesser worth.[70] Another theory suggests that the word "Genghis" bears connotations of strength, firmness, hardness, or righteousness.[71] A third hypothesis proposes that the title is related to the Turkic "tängiz", meaning "sea" or "ocean"; the title "Genghis Khan" would mean "master of the ocean", and as the ocean was believed to surround the earth, the title ultimately implied "Universal Ruler".[72]

Having attained control over one million people and over fifteen million animals,[73] Genghis Khan began what May has termed a "social revolution".[74] As traditional tribal systems had primarily evolved to benefit small clans and families, they were unsuitable as the foundations for larger states and had been the downfall of previous steppe confederations. Aware that a different organisational structure was required for the functioning of his new nation, Genghis began a series of administrative reforms designed to suppress the power of tribal loyalties and to replace them with unconditional loyalty to the khan and the ruling family.[75] As most of the traditional tribal leaders had been killed during his rise to power, Genghis was able to reconstruct the Mongol social hierarchy in his favour. The highest tier was occupied solely by the families of the Khan and his brothers, who became known as the altan uruq (lit. "Golden Family") or chaghan yasun (lit. "white bone"); underneath them came the qara yasun (lit. "black bone"; sometimes qarachu), composed of the surviving pre-empire aristocracy and the most important of the new families.[76]

To break any concept of tribal loyalty, the entirety of Mongol society was reorganised into a decimal system of military organisation. Every man between the age of fifteen and seventy was conscripted into a minqan (PL minkad), a unit of a thousand soldiers, which was further subdivided into units of hundreds (jaghun, PL jaghat) and tens (arban, PL arbat).[77] The units also encompassed each man's household, meaning that each military minqan was supported by a minqan of households in a defined military–industrial complex. Each minqan operated as both political and social units, while the warriors of defeated tribes were dispersed to different minqad so that they could not rebel as a single body. This was intended to ensure the disappearance of old tribal identities, replacing them with loyalty to the Yeke Mongol Ulus (lit. "Great Mongol State") and to commanders who had gained their rank through meritocratic skill and loyalty to the khan.[78] This particular reformation proved extremely effective—even after the division of the Mongol Empire, fragmentation never happened along tribal lines. Instead, the Borjigin Genghisids continued to reign unchallenged, in some cases until as late as the 1700s, and even powerful non-imperial dynasts such as Timur and Edigu were compelled to rule from behind a Genghisid puppet ruler.[79]

Modern statue of Muqali in Sükhbaatar Square, Ulaanbaatar

16th-century Chinese engraving depicting Subutai

Genghis' senior nökod were appointed to the highest ranks and received the greatest honours. Bo'orchu and Muqali were each given ten thousand men (tumen, PL tumed) to lead as commanders of the right and left wings of the army respectively.[80] The other nökod were given commands of one of the ninety-five minkad. Many of these men were born to low social status: Ratchnevsky cites Jelme and Subutai, the sons of blacksmiths, in addition to a carpenter, a shepherd, and even the two herdsmen who had warned Temüjin of Toghrul's plans in 1203.[81] As a special privilege, Genghis allowed certain loyal commanders to retain the tribal identities of their units. Alakush of the Ongud was allowed to retain five thousand warriors of his tribe because his son had married Genghis' daughter Alakhai Bekhi, while Chigu and Alchi of the Onggirat, as husband to Genghis' sister Temülen and brother to Börte respectively, were granted three minkad each. These large exemptions were bestowed because of existing quda (lit. "marriage alliance") pacts.[82]

A key tool which underpinned these reforms was the expansion of the keshig (lit. "bodyguard"). After Temüjin's defeat of Toghrul in 1203, he had appropriated this Kereit institution in a minor form, but at the 1206 kurultai its numbers were greatly expanded, from 1,150 to 10,000 men. The keshig was not only the khan's bodyguard, but his household staff, a military academy, a guarantor of loyalty, and the basis of governmental administration.[83] All the warriors in this elite corps, divided into an 8,000-strong day guard and two minqad of night guards and quiver bearers, were brothers or sons of military commanders, and were essentially hostages. The keshigten (lit. "keshig members") nevertheless received special privileges and direct access to the khan, whom they would serve in all respects during both peace and war, and who in return would evaluate their capabilities and their potential to govern or command.[84][lower-alpha 3]

From 1206 to 1209, Genghis Khan was predominantly focused on consolidating and maintaining his new nation.[86] He faced a challenge from Kokechu, the son of Münglig, the trusted retainer of Yesügei to whom Genghis had given his mother Hö'elün in marriage. Kokechu was the shaman who had proclaimed Temüjin as Genghis Khan and taken the Tengrist title "Teb Tenggeri" (lit. "Wholly Heavenly") on account of his sorcery. He was very influential among the Mongol commoners and sought to divide the imperial family.[87] Genghis' oldest sibling Qasar was the first of Kokechu's targets—always distrusted by his brother, he was humiliated and almost imprisoned on false charges before Hö'elün intervened by publicly reprimanding her eldest son. Nevertheless, Kokechu's power steadily increased. When Genghis' youngest brother Temüge attempted to intervene he too was publicly shamed.[88] Börte saw the threat Kokechu posed and warned Genghis, who still superstitiously revered the shaman; relenting, he allowed Temüge to assassinate Kokechu and usurped the shaman's position as the Mongols' highest spiritual authority.[89]

During these years, the Mongols imposed their control on surrounding areas. Genghis dispatched Jochi northwards in 1207 to subjugate the Hoi-yin Irgen, a collection of tribes on the edge of the Siberian taiga, and, having secured a marriage alliance with the Oirats and defeated the Yenisei Kyrgyz, took control of the region's grain trade, fur trade, and gold mines.[90] Mongol armies also rode westwards, defeating the Naiman-Merkit alliance on the River Irtysh in late 1208. Their khan was killed and Kuchlug fled into Central Asia.[91] Led by Barchuk, the Uyghurs freed themselves from the suzerainty of the Qara-Khitai and pledged themselves to Genghis in 1211 as the first sedentary society to submit to the Mongols.[92]

The states of East and Central Asia in the early 13th century

The Mongols had started raiding the border settlements of the Tangut-led Western Xia kingdom in 1205, ostensibly in retaliation for allowing Senggum, Toghrul's son, refuge;[93] more prosaic explanations include rejuvenating the depleted Mongol economy with an influx of fresh goods and livestock,[94] or simply subjugating a semi-hostile state to protect the nascent nation.[95] Most Xia troops were stationed along the southern and western borders of the kingdom to guard against attacks from the Song and Jin dynasties respectively, while its northern border relied only on the Gobi desert for protection, unlike the Jin's which was strongly fortified.[96] After a raid in 1207 sacked the fortress of Wulahai, Genghis decided to personally lead a full-scale invasion in 1209.[97]

Wulahai was captured again in May and the Mongols advanced on the capital Zhongxing (modern-day Yinchuan) but suffered a reverse against a Xia army. After a two-month stalemate, Genghis broke the deadlock with a successfully-executed feigned retreat.[98] Although Zhongxing was now mostly undefended, lacking any siege equipment better than crude battering rams, the Mongols were unable to progress the siege.[99] Genghis' innovative attempt to redirect the Yellow River into the city with a dam initially worked, but the poorly-constructed earthworks broke—possibly breached by the Xia—in January 1210 and the Mongol camp was flooded, forcing them to retreat. A peace treaty was soon formalized: the Xia emperor Xiangzong submitted and handed over tribute, including his daughter Chaka, in exchange for the Mongol withdrawal.[100]

Depictions of Mongol-Jin conflict from manuscripts of the Jami al-tawarikh. From top: the Battle of Yehuling (1211); a skirmish between Mongol and Jin cavalry; Genghis entering Zhongdu after capturing it in 1215.

Wanyan Yongji usurped the Jin throne in 1209. He had previously served on the steppe frontier and Genghis greatly disliked him;[101] he also declined to aid the Xia against the Mongols.[102] When asked to submit and pay the annual tribute to Yongji in 1210, Genghis instead mocked the emperor, spat, and rode away from the Jin envoy—a challenge which meant war.[103] He had made preparations for an invasion of Jin, despite the possibility of being outnumbered eight-to-one by 600,000 Jin soldiers, since learning of their internal instabilities in 1206.[104] Genghis had two aims: to take vengeance for past wrongs committed by the Jin, foremost among which was the death of Ambaghai Khan in the mid-12th century, and to win the vast amounts of plunder his troops and vassals expected.[105]

After calling for a kurultai in March 1211, Genghis launched his invasion of Jin China in May, reaching the outer Jin defense ring the following month. These border fortifications were guarded by the Ongud tribe, who were friendly to the Mongols—through his daughter Alakhai Beki, Genghis held a quda alliance with their leader Alaqush—and allowed them to pass without difficulty.[106] The three-pronged chevauchée aimed both to plunder and burn a vast area of Jin territory to deprive them of supplies and popular legitimacy, and to secure the mountain passes which allowed access to the North China Plain.[107] The Jin lost numerous towns and were hindered by a series of defections, the most prominent of which was Khitan Shimo Ming'an, whose betrayal led directly to Muqali's victory at the Battle of Huan'erzhui in autumn 1211.[108] The campaign was halted in 1212 when Genghis was wounded by an arrow during the siege of Xijing (modern Datong).[109] Following the failure at Xijing, Genghis set up a corps of siege engineers, which recruited 500 Jin experts over the next two years.[110]

The defenses of Juyong Pass had been strongly reinforced by the time the conflict resumed in 1213, but a Mongol detachment led by Jebe managed to infiltrate the pass and surprise the elite Jin defenders, opening the road to the Jin capital Zhongdu (modern-day Beijing).[111] The Jin administration began to disintegrate: after the Khitans entered open rebellion, Hushahu, the commander of the forces at Xijing, abandoned his post and staged a coup in Zhongdu, killing Yongji and installing his own puppet ruler, Xuanzong.[112] This governmental breakdown was fortunate for Genghis' forces—emboldened by their victories, they had seriously overreached and lost their initiative. Unable to do more than sit before Zhongdu's fortifications while his army suffered from an epidemic and famine. The Mongols are reported to have resorted to cannibalism. Genghis opened peace negotiations despite his commanders' militarism.[113] He secured tribute, including 3,000 horses, 500 slaves, a Jin princess, and massive amounts of gold and silk, before breaking the siege in spring 1214 and setting off homewards in May 1214.[114]

With the northern Jin lands ravaged by plague and the Mongols, Xuanzong decided to move the capital and imperial court 600 kilometres (370 mi) southwards to Kaifeng.[115] Genghis saw this move as a betrayal of the peace treaty and immediately prepared to return, even though he had been away from home for three years.[116] According to Christopher Atwood, it was only at this juncture that Genghis decided to fully conquer northern China.[117] Muqali captured numerous towns in Liaodong during winter 1214–15, and although the inhabitants of Zhongdu surrendered to Genghis on 31 May 1215, the city was sacked and looted.[118] When Genghis returned to Mongolia in early 1216, Muqali was left in command in China.[119] He waged a brutal but effective campaign against the unstable Jin until his death in 1223.[120]

In 1207, Genghis had appointed a man named Qorchi as governor of the subdued Hoi-yin Irgen tribes. Appointed not for his talents but for prior services rendered, Qorchi was a poor choice, and his habit of taking too many concubines for his harem led the tribes to rebel and take him prisoner in early 1216. Boroqul, one of Genghis' highest-ranking nökod, was ambushed and killed the following year.[121] The khan was livid at the loss of his close friend and prepared to personally lead a retaliatory campaign; eventually dissuaded from this course, he dispatched his eldest son Jochi and a Dörbet commander. They managed to surprise and defeat the rebels, securing control over this economically important region.[122]

Kuchlug, the Naiman prince who had been defeated in 1204, had usurped the throne of the Central Asian Qara Khitai dynasty between 1211 and 1213. He was a greedy and arbitrary ruler who probably earned the enmity of the native Islamic populace whom he attempted to forcibly convert to Buddhism.[123] Genghis sensed that Kuchlug might be a potential threat to his empire, and Jebe was sent with an army of 20,000 cavalry to Kashgar; he undermined Kuchlug's rule by emphasising the Mongol policies of religious tolerance and gained the loyalty of the local elite.[124] Kuchlug was forced to flee southwards to the Pamir Mountains, but was captured by local hunters. Decapitated by the Mongols, his corpse was paraded through Qara Khitai, and Jebe proclaimed the end of religious persecution in the region.[125]

Campaigns of Genghis Khan between 1207 and 1225

Genghis had now attained complete control of the eastern portion of the Silk Road, and his territory bordered that of the Khwarazmian Empire, which ruled over much of Central Asia, Persia and Afghanistan.[126] Merchants from both sides were eager to restart trading, which had halted during Kuchlug's rule—the Khwarazmian ruler Muhammad II dispatched an envoy shortly after the Mongol capture of Zhongdu, while Genghis instructed the ortoq, the Mongol trading partners, to obtain the high-quality textiles and steel of Central and Western Asia.[127] Many members of the altan uruq invested in one particular caravan of 450 merchants which set off to Khwarazmia in 1218 with a massive quantity of goods. Muhammad had however grown suspicious of Genghis' intentions, and when Inalchuq, the governor of the Khwarazmian border town of Otrar, decided to halt the caravan, massacre the merchants on grounds of espionage, and seize the goods, the Khwarazmshah either supported Inalchuq or turned a blind eye.[128] A Mongol ambassador was sent with two companions to avert war, but he was killed and his companions humiliated. The killing of an envoy infuriated Genghis, who resolved to leave Muqali with a small force in North China and invade Khwarazmia with most of his army.[129]

Muhammad's empire was large but disunited: he ruled alongside his mother Terken Khatun in what Peter Golden termed "an uneasy diarchy", while the Khwarazmian nobility and populace were discontented with his warring and centralization of government. For these reasons and others he declined to meet the Mongols in the field, instead garrisoning his unruly troops in his major cities.[130] This allowed the lightly armoured, highly mobile Mongol armies uncontested superiority outside city walls.[131] Otrar was besieged in autumn 1219—the siege dragged on for five months, but in February 1220 the city fell and Inalchuq was executed.[132] Genghis had meanwhile divided his forces. Leaving his sons Chagatai and Ogedei besieging the city, he had sent Jochi northwards down the Syr Darya river and another force southwards into central Transoxiana, while he and Tolui took the main Mongol army across the Kyzylkum Desert, surprising the garrison of Bukhara in a pincer movement.[133]

Depiction of Jalal al-Din crossing the Indus River, from a late 17th-century Jami al-tawarikh manuscript

Bukhara's citadel was captured in February 1220 and Genghis moved against Muhammad's residence Samarkand, which fell the following month.[134] Bewildered by the speed of the Mongol conquests, Muhammad fled from Balkh, closely followed by Jebe and Subutai; the two generals pursued the Khwarazmshah until his death from dysentry on a Caspian Sea island in winter 1220/21. Before his death, he nominated his eldest son Jalal al-Din as his successor.[135] Jebe and Subutai then set out on a massive 7,500 kilometres (4,700 mi) expedition around the Caspian Sea. Later called the Great Raid, this lasted four years and saw the Mongols come into contact with medieval Europe for the first time.[136] Meanwhile, the Khwarazmian capital of Gurganj was being besieged by Genghis' three eldest sons; a long siege ended in spring 1221 amid brutal urban conflict.[137] Jalal al-Din moved southwards to Afghanistan, gathering forces on the way and defeating a Mongol unit under the command of Shigi Qutuqu, Genghis' adopted son, in the Battle of Parwan.[138] Jalal was weakened by arguments among his commanders, and losing decisively at the Battle of the Indus in November 1221, he was compelled to swim across the river into India.[139]

Genghis' youngest son Tolui was concurrently conducting a brutal campaign in the regions of Khorasan. Every city that resisted was destroyed in a programme of concentrated devastation—Nishapur, Merv and Herat, three of the largest and wealthiest cities in the world, were all annihilated.[lower-alpha 4][141] This campaign established Genghis' lasting image as a ruthless, inhumane conqueror. Persian historians placed the death toll from the three sieges alone at over 5.7 million—numbers regarded as grossly exaggerated by modern scholarship.[142] Nevertheless, even a total death toll of 1.25 million for the entire campaign, as estimated by John Man, would have been a demographic catastrophe.[143]

Genghis abruptly halted his Central Asian campaigns in 1221.[144] Initially aiming to return via India, Genghis realised that the heat and humidity of the South Asian climate impeded his army's skills, while the omens were additionally unfavourable.[145] Although the Mongols spent much of 1222 repeatedly overcoming rebellions in Khorasan, they withdrew completely from the region to avoid overextending themselves, setting their new frontier on the Amu Darya river.[146] During his lengthy return journey, Genghis prepared a new administrative division which would govern the conquered territories, appointing darughachi (commissioners, lit. "those who press the seal") and basqaq (local officials) to manage the region back to normalcy.[147] He also summoned and spoke with the Daoist patriarch Changchun in the Hindu Kush. The khan listened attentively to Changchun's teachings and granted his followers numerous privileges, including tax exemptions and authority over all monks throughout the empire—a grant which the Daoists would later use to try to gain superiority over Buddhism.[148]

The usual reason given for the halting of the campaign is that the Western Xia, having declined to provide auxiliaries for the 1219 invasion, had additionally disobeyed Muqali in his campaign against the remaining Jin in Shaanxi province.[144] May has disputed this, arguing that the Xia fought in concert with Muqali until his death in 1223, when, frustrated by Mongol control and sensing an opportunity with Genghis in Central Asia, they ceased fighting.[149] In either case, Genghis initially attempted to resolve the situation diplomatically, but when the Xia elite failed to come to an agreement on the hostages they were to send to the Mongols, he lost patience.[150] Returning to Mongolia in early 1225, he spent the year in preparation for the campaign, which began in the first months of 1226 with the capture of Khara-Khoto on the Xia's western border.[151]

The invasion proceeded apace. Genghis ordered that the cities of the Gansu Corridor be sacked one by one, granting clemency only to a few.[152] Having crossed the Yellow River in autumn, the Mongols besieged present-day Lingwu, located just 30 kilometres (19 mi) south of the Xia capital Zhongxing in November. On 4 December, Genghis decisively defeated a Xia relief army; the khan left the siege of the defenceless capital to his generals and moved southwards with Subutai to plunder and secure Jin territories.[153]

Early 15th-century miniature of Genghis Khan advising his sons on his deathbed, taken from Marco Polo's section of the Livre des merveilles manuscript.[162]

The tribes of the Mongol steppe had no fixed succession system, but often defaulted to some form of ultimogeniture—succession of the youngest son—on the grounds that unlike his older brothers, the youngest son would not have had time to gain a following for himself and needed the help of his father's inheritance.[163] However, it has been noticed that this inheritance applied only to property, not to titles.[164] Through the Mongol appanage system, Genghis allocated lands and populations as property to each member of his close family. His brothers Qasar, Hachiun, Temüge, and Belgutei were given lands along the Greater Khingan mountains in the east,[165] and the lands of his three elder sons were located in the west: for Jochi, along the Irtysh river, extending into Siberia and the territory of the Kipchaks; for Chagatai, the former Qara Khitai territories surrounding Almaligh in Turkestan; for Ogedei, lands in Dzungaria;[lower-alpha 5] and for Tolui the Mongolian fatherland near the Altai Mountains, as per tradition.[167]

The Secret History records that he chose his successor at the behest of his wife Yisui while preparing for the Khwarazmian campaigns in 1219; Rashid al-Din, on the other hand, states that the decision came before Genghis' final campaign against the Xia.[168] Regardless of the date, there were five possible candidates: Genghis' four sons and his youngest brother Temüge, who had the weakest claim and who was never seriously considered.[169] Even though there was a strong possibility Jochi was illegitimate Genghis was not particularly concerned by this;[170] nevertheless, he and Jochi became increasingly estranged over time. This was due to Jochi's preference for remaining in and growing his own appanage; his actions during the Siege of Gurganj, where his reluctance to destroy a wealthy city that would become part of his territory eventually led to his failure to give Genghis the khan's share of the booty, exacerbated the tensions.[171] Genghis was angered by Jochi's refusal to return to him in 1223, allegedly because of his love for hunting, and was considering sending Ogedei and Chagatai to bring him back to heel when news came that Jochi had prematurely died from a serious illness.[172]

Chagatai's attitude towards Jochi's possible succession—he had termed his elder brother "a Merkit bastard" and had brawled with him in front of their father—led Genghis to view him as uncompromising, arrogant, and narrow-minded, despite his great knowledge of Mongol legal customs.[173] His elimination left Ogedei and Tolui as the two primary candidates. Tolui was unquestionably superior in military terms—his campaign in Khorasan had broken the Khwarazmian Empire, while his elder brother was far less able as a commander.[174] Ogedei was also known to drink excessively even by Mongol standards—it was eventually the cause of his death in 1241.[175] However, he possessed talents all his brothers lacked—he was generous and courteous, well-liked by all in the nation. Aware of his own lack of military skill, he was able to trust his capable subordinates, and unlike his elder brothers, compromise on issues; he was also more likely to preserve Mongol traditions than Tolui, whose wife Sorghaghtani, herself a Nestorian Christian, was a patron of many religions including Islam. Ogedei was thus recognised as the heir to the Mongol throne.[176]

Serving as regent after Genghis' death, Tolui established a precedent for the customary traditions after khan's death. These included: the halting of all offensive military actions involving Mongol troops, the establishment of a lengthy mourning period, which the regent would oversee, and the holding of a kurultai which would nominate successors and select them.[177] For Tolui, this presented an opportunity. He was still a viable candidate for succession and had the support of the family of Jochi. Any general kurultai, attended by the commanders Genghis had promoted and honoured, would however observe their former ruler's desires without question and appoint Ogedei as ruler. It has been suggested that Tolui's reluctance to hold the kurultai was driven by the knowledge of the threat it posed to his ambitions.[178] In the end, Tolui had to be convinced by Yelu Chucai to hold the kurultai; in 1229, it crowned Ogedei as khan, with Tolui in attendance.[179]

Genghis Khan and Great Khans of the Yuan dynasty, late 13th and early 14th-century Yuan paintings

Genghis Khan never allowed his image to be depicted in any medium; as a result, any painting, sculpture, or engravings are interpretations of the writings of historians, most writing long after his death.[180] The two earliest statements come from the Persian chronicler Juzjani, who relied on Khorasani eyewitnesses, and the contemporary Song diplomat Zhao Hong—both record that he was tall and strong with a powerful stature. Juzjani additionally remarks on the khan's "cat's eyes", mirroring a similar statement Dei Sechen, Genghis' father-in-law, is recorded saying on meeting him as a nine-year old.[181] Another written description is found in the Jami al-tawarikh, which states that Genghis Khan and his Borjigin ancestors had blue-green eyes and either red hair or a ruddy complexion which Kublai Khan did not inherit. The factual nature of this description is considered controversial.[182][183]

Genghis Khan had a notably positive reputation among some western European authors in the Middle Ages, who knew little concrete information about his empire in Asia.[184] The Italian explorer Marco Polo said that Genghis Khan "was a man of great worth, and of great ability, and valor",[185][186] while philosopher and inventor Roger Bacon applauded the scientific and philosophical vigor of Genghis Khan's empire,[187] and Geoffrey Chaucer praised the "great renown of Cambinskan".[188]

A bust of Genghis Khan in the presidential palace in Ulaanbaatar, and a statue of him at his mausoleum

During the communist period in Mongolia, Genghis was often described by the government as a reactionary figure, and positive statements about him were avoided.[189] In 1962, the erection of a monument at his birthplace and a conference held in commemoration of his 800th birthday led to criticism from the Soviet Union and the dismissal of secretary Tömör-Ochir of the ruling Mongolian People's Revolutionary Party Central Committee.

In the early 1990s, the memory of Genghis Khan underwent a powerful revival, partly in reaction to its suppression during the Mongolian People's Republic period. Genghis Khan became a symbol of national identity for many younger Mongolians, who maintain that the historical records written by non-Mongolians are unfairly biased against Genghis Khan and that his butchery is exaggerated, while his positive role is underrated.[190]

In Mongolia today, Genghis Khan's name and likeness appear on products, streets, buildings, and other places. His face can be found on everyday commodities, and on the largest denominations of 500, 1,000, 5,000, 10,000, and 20,000 Mongolian tögrög (₮). Mongolia's main international airport in Ulaanbaatar is named Chinggis Khaan International Airport, and there is a 40m-high equestrian statue of Genghis Khan east of the Mongolian capital. There has been talk about regulating the use of his name and image to avoid trivialization.[191] Genghis Khan's birthday, on the first day of winter (according to the Mongolian lunar calendar), is a national holiday.[192]