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Mongol invasion of Khwarezmia and Eastern Iran

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Invasion of Khwarezmia
Part of the Mongol invasions
Khwarezmian Empire 1190 - 1220 (AD).PNG
Khwarezmid Empire (1190-1220)
Date 1218 - 1221
Location Central Asia
Result Complete Mongol victory
Khwarezmia added to the Mongol Empire
Mongol Empire Khwarezmia
Commanders and leaders
Genghis Khan,
Ala ad-Din Muhammad,
Jalal Al-Din,
Inalchuq† (executed)
mounted archers, with powerful siege engines
400,000 men, however not organized into armies, only city garrisons and very low draft rate left the majority unmobilized.
Casualties and losses
10,000 killed 150,000 killed,
2.5-4 million civilians

The Mongol invasion of Khwarezmia lasted from 1219 to 1221. It marked the beginning of the Mongol Conquest of the Islamic States, and it also expanded the Mongol invasions, which would ultimately culminate in the conquest of virtually the entire known world, save for Western Europe, Fennoscandia, the Byzantine Empire, Arabia, Africa, Indian subcontinent, Japan and parts of Southeast Asia.

Ironically, it was not originally the intention of the Mongol Khanate to invade the Khwarezmid Empire. Indeed, Genghis Khan had originally sent the ruler of the Khwarezmid Empire, Ala ad-Din Muhammad , a message greeting him as his equal: "you rule the rising sun and I the setting sun." The Mongols' original unification of all "people in felt tents", unifying the nomadic tribes in Mongolia and then the Turcomens and other nomadic peoples, had come with relatively little bloodshed, and almost no material loss. Even his invasions of China, to that point, had involved no more bloodshed than previous nomadic invasions had caused.

It would be the invasion and utter destruction and complete devastation of the Khwarezmid Empire which would earn the Mongols the name for bloodthirsty ferocity that would mark the remainder of their campaigns. In this brief war, lasting less than two years, not only was a huge empire destroyed utterly, but Genghis Khan introduced the world to tactics that would not be seen again until the Germans used them so well in World War II - indirect attack, and complete and utter terror and slaughter of populations wholesale as weapons of war.

Origins of the conflict

After the defeat of the Kara-Khitais, Genghis Khan's Mongol Empire had a border with the Khwarezmid Empire, governed by Shah Ala ad-Din Muhammad. The Shah had only recently taken some of the territory under his control, and he was also busy with a dispute with the caliph in Baghdad. The Shah had refused to make the obligatory homage to the Caliph as titular leader of Islam, and demanded recognition as Sultan of his Empire, without any of the usual bribes, or pretend homage. This alone had created him problems along his southern border. It was at this junction the Mongol Empire, expanding incredibly, made contact. It is possible that Genghis Khan's long term goal was to take advantage of the internal instability of the Shah's empire. However, in the short term, it is clear that Genghis Khan saw the potential advantage in Khwarezmia as a commercial partner and started a correspondence with the shah in 1218 in order to establish trade between their empires. Mongol history is adamant that the Great Khan at that time had no intention of invading the Khwarezmid Empire, and was only interested in trade and even a potential alliance. (It must be noted that Genghis Khan eventually abrogated every allegiance he ever made, but in the short term, he probably did not intend to invade the Khwarezmid Empire when he did)

The shah was very suspicious of Genghis' want for a trade agreement and messages from the shah's ambassador at Zhongdu in China describing the exaggerated savagery of the Mongols when they assaulted the city during their war with the Jin Dynasty. Of further interest is that the caliph of Baghdad, An-Nasir, had attempted to instigate a war between the Mongols and the Shah some years before the Mongol invasion actually occurred. This attempt at an alliance with Genghis was done because of a dispute between Nasir and the Shah, but the Khan had no interest in alliance with any ruler who claimed ultimate authority, titular or not, and which marked the Caliphate for an extinction which would come from Genghis' grandson, Hulegu. At the time, this attempt by the Caliph involved the Shah's ongoing dispute with wanting to be named sultan of Khwarezm, something that Nasir had no wish to do, as the Shah refused to acknowledge his authority, however illusory such authority was. However, it is known that Genghis rejected the notion of war as he was engaged in war with the Jin Dynasty and was gaining much wealth from trading with the Khwarezmid Empire.

Genghis then sent a 500-man caravan of Muslims to officially establish trade ties with Khwarezmia. However Inalchuq, the governor of the Khwarezmian city of Otrar, had the members of the caravan that came from Mongolia arrested, claiming that the caravan was a conspiracy against Khwarezmia. It seems unlikely, however, that any members of the trade delegation were spies. Nor does it seem likely that Genghis was trying to provoke a conflict with the Khwarezmid Empire, considering he was still dealing with the Jin in northeastern China.

Genghis Khan then sent a second group of three ambassadors (one Muslim and two Mongols) to meet the shah himself and demand the caravan at Otrar be set free and the governor be handed over for punishment. The shah had both of the Mongols shaved and had the Muslim beheaded before sending them back to Genghis Khan. Muhammad also ordered the personnel of the caravan to be executed. This was seen as a grave affront to the Khan himself, who considered ambassadors "as sacred and inviolable." This led Genghis Khan to attack the Khwarezmian Dynasty. The Mongols crossed the Tien Shan mountains, coming into the Shah's empire in 1219.

Initial Invasion of Khwarezmia

After compiling information from many intelligence sources, primarily from spies along the Silk Road, Genghis Khan carefully prepared his army, which was organized differently from Genghis' earlier campaigns. (see " Mongol military tactics and organization" for overall coverage). The changes had come in adding supporting units to his dreaded cavalry, both heavy and light. While still relying on the traditional advantages of his mobile nomadic cavalry, Genghis incorporated many aspects of warfare from China, particularly in siege warfare. His baggage train included such siege equipment as battering rams, gunpowder, trebuchets, and enormous siege bows capable of throwing 20-foot arrows into siege works. Also, the Mongol intelligence network was formidable. The Mongols never invaded an opponent whose military and economic will and ability to resist had not been thoroughly and completely scouted. For instance, Subutai and Batu Khan spent a year scouting central Europe, before destroying the armies of Hungary and Poland in two separate battles, two days apart.

The size of Genghis' army is often in dispute, ranging from a small army of 90,000 soldiers to a larger estimate of 250,000 soldiers, and Genghis brought along his most able generals to aide him, the dreaded "dogs of war". Genghis also brought a large body of foreigners with him, primarily of Chinese origin. These foreigners were siege experts, bridge-building experts, doctors and a variety of speciality soldiers.

A minaret in Samarkand.

But it is vital to note at this juncture that it was in this invasion that the Khan first demonstrated the concept of indirect attack, that would so mark his career, and even that of his sons and grandsons. The Khan divided his armies, and literally sent one force solely to find and execute the Shah - so that a ruler of an Empire as large as the Mongols, with an army which was larger, was literally forced to run for his life in his own country, as various Mongol armies decimated his forces piecemeal, and began the utter devastation of the country which would so terribly mark their other conquests in history.

The Shah's army, numbered roughly 400,000, was split among the various major cities. This was done because of two reasons. Firstly, the Shah was fearful of his army being in one large unit. He did not want the army to be under a single command structure, one that could possibly be turned against him. Secondly, the Shah's reports from China seemed to indicate that the Mongols were not experts in siege warfare and experienced problems attempting to take fortified positions. This proved to be a disastrous decision on the Shah's part as the campaign unfolded.

Tired and exhausted from the journey, the Mongols still won their first victories against the Khwarezmian army. A Mongol army, under Jochi, with 25,000 to 30,000 men, attacked the Shah's army in southern Khwarezmia and prevented the much larger Shah army from forcing them into the mountains. The primary Mongol army, headed personally by the Khan, quickly sieged the town of Otrar, reaching the city in the fall of 1219. For five months Genghis sieged the city before he managed to storm the main part of the city, by entering a sally port gate that was not secured.

Another month went by before the citadel at Otrar was taken. Inalchuq held out until the end, even climbing to the top of the citadel in the last moments of the siege, throwing down tiles at the oncoming Mongols. Genghis killed many of the inhabitants, enslaving the rest, and executed Inalchuq by pouring molten gold through his throat, as retribution for the death of Genghis' caravan.

Ruins of Muhammad's palace in Urgench.

Sieges of Bukhara, Samarkand, and Urgench

Genghis had sent one of his generals, Jebe, far to the south, at the head of a small army, intending to cut off any retreat by the Shah to the southern half of his kingdom. Further, Genghis and Tolui, at the head of an army of roughly 50,000 men, skirted past Samarkand and went westwards, intending to siege the western city of Bukhara first. To do this, they traversed the seemingly impassable Kyzl Kum desert by hopping through the various oases, guided most of the way by captured nomads. The Mongols would arrive at the gates of Bukhara almost entirely unnoticed. Many military tacticians regard this surprise entrance to Bukhara one of the most successful surprise attacks in warfare.

Bukhara was not heavily fortified, with a moat and a single wall, plus the typical citadel that every Khwarezmi town had. The garrison at Bukhara was made up of Turkish soldiers and led by Turkish generals. They attempted to break out on the third day of the siege, but the break out force, comprising as many as 20,000 men, were annihilated in open battle. The city leaders opened the gates to Bukhara, though a unit of Turkish defenders held the city's citadel for another twelve days. Survivors from the citadel were executed, artisans and craftsmen were sent back to Mongolia, young men who had not fought were drafted into the Mongolian army and the rest of the population was sent into slavery. This was to be Genghis' typical treatment of captured cities throughout the rest of the campaign. As the Mongol soldiers looted the city, a fire broke out, razing the majority of the city to the ground. Genghis Khan had the people assemble in the main mosque of the town, where he declared that he was the flail of God, sent to punish them for their sins before ordering their execution.

After the fall of Bukhara, Genghis headed west, towards the Khwarezmi capital of Samarkand and arrived at the city in March 1220. Samarkand was significantly more fortified and there were as many as 100,000 men defending the city. As Genghis began besieging the city, his sons Chaghatai and Ögedei joined him after finishing off the reduction of Otrar and the joint Mongol forces launched an assault on the city. Using prisoners as body shields, the Mongols attacked. On the third day of fighting, the Samarkand garrison launched a counterattack. Feigning retreat, Genghis reportedly drew out a garrison force of 50,000 outside the fortifications of Samarkand and slaughtered them in open combat. Muhammad attempted to relieve the city twice, but was driven back. On the fifth day, all but an approximate 2,000 soldiers surrendered. The remaining soldiers, die-hard supporters of the Shah, held out in the citadel. After the fortress fell, Genghis reneged on his surrender terms and executed every soldier that had taken arms against him at Samarkand. The people of Samarkand were asked to evacuate the city and assembled in a plain outside the city, where they were killed and pyramids of severed heads raised as the symbol of Mongol victory.

Around the fall of Samarkand, Genghis Khan charged Subutai and Jebe, two of the Khan's top generals, with hunting down the Shah, who had fled westwards to escape the Mongols. The Shah fled with some of his diehard soldiers and his son, Jalal Al-Din, towards the shores of the Caspian Sea, where he was taken to a small island out in the sea. It was there that the Shah died. Most scholars attribute his death to pneumonia, but others cite the sudden shock of the loss of his empire and his power. This was in December 1220. Meanwhile, the wealthy trading city of Urgench was still in the hands of Khwarezmian forces. Previously, the Shah's mother had ruled there, but she fled and was captured when she learned her son had fled to the Caspian Sea. She was imprisoned and sent back to Mongolia. One of Muhammad's generals, a man by the name of Khumar Tegin, had declared himself Sultan of Urgench. Jochi, who had been on campaign in the north since the invasion, approached the city from that direction, whereas Genghis, Ögedei, and Chaghatai attacked Urgench from the south.

The siege and assault on Urgench proved to be the hardest battle in the entire course of the invasion. The city was built along the river Amu Darya in a marshy delta area. The soft ground did not lend itself to siege warfare, and there was a lack of large stones for the catapults. The Mongols assaulted regardless, and after the defenders put up a stout defense, fighting block for block, the city fell. Mongolian casualties were higher than normal, due to the difficult city fighting that did not lend well to Mongolian tactics. The taking of Urgench was further complicated by Genghis' eldest son, Jochi, who had been promised the city as his prize. It must be noted that there had always been tension between Jochi and his father. It was this battle, that brought that tension to a point it would mean permanent estrangement between the two. Jochi's mother was the same as his three brothers, Genghis's "official" sons. Genghis Khan's teen bride, and apparent lifelong love, was Borte - only her sons would command as sons of the Khan, not the illegitimate sons conceived by the Khan's 500 or so other "wives and consorts." But Jochi had been conceived in controversy. Borte was captured in the early days of the Khan's rise, and held prisoner while she was raped. Jochi was born nine months later, and while Genghis Khan chose to acknowledge him as his oldest son, (primarily due to his love for Borte, whom he would have had to reject if he rejected her child) tension always existed over Jochi's true parentage. Ultimately, the single quarrel would destroy the unity of the Mongol Empire. But the tension was present as Jochi engaged in negotiations with the defenders, trying to get them to surrender so that as little of the city as possible was undamaged. This angered Chaghatai, and Genghis headed off this sibling fight by appointing Ögedei the commander of the sieging forces and Urgench fell. But the removal of Jochi from command, and the sack of a city he considered promised his, enraged him, estranged him from his brothers, and is credited with being essentially the final straw for a man who saw his younger brothers being promoted over him, despite his own considerable military skills. As usual, the artisans were sent back to Mongolia, the young women and children were given to the Mongol soldiers as slaves, and the rest of the population was massacred. The Persian scholar Juvayni states that 50,000 Mongol soldiers were given the task of executing twenty-four Urgench citizens each, which would mean that 1.2 million people were killed. While this is almost certainly exaggeration, the sacking of Urgench is considered one of the bloodiest massacres in human history.

Next was the city of Gurjang, south of the Aral Sea, where upon its surrender the Mongols broke the dams and flooded the city, then proceeding to execute the survivors.

The Khorasan Campaign

As the Mongols battered their way into Urgench, Genghis dispatched his youngest son Tolui, at the head of an army, into the western Khwarezmid province of Khorasan. Khurasan had already felt the strength of Mongol arms. Earlier in the war, the generals Jebe and Subatai had travelled through the province while hunting down the fleeing Shah. However, the region was far from subjugated, many major cities remained free of Mongol rule, and the region was rife with rebellion against the few Mongol forces present in the region after the rumors of Jalal Al-Din gathering an army to fight against the Mongols. Tolui's army consisted of somewhere around 50,000 men, which was composed of a core of Mongol soldiers (some estimates place it at 7,000), supplemented by a large body of foreign soldiers, such as Turks and previously conquered peoples in China and Mongolia. The army also included "3,000 machines flinging heavy incendiary arrows, 300 catapults, 700 mongonels to discharge pots filled with naphtha, 4,000 storming-ladders, and 2,500 sacks of earth for filling up moats." Among the first cities to fall was Termez then Balkh. The major city to fall to Tolui's army was the city of Merv. Juvayni wrote of Merv: "In extent of territory it excelled among the lands of Khorasan, and the bird of peace and security flew over its confines. The number of its chief men rivaled the drops of April rain, and its earth contended with the heavens."

The garrison at Merv was only about 12,000 men, and the city was inundated with refugees from eastern Khwarezmid. For six days, Tolui besieged the city, and on the seventh day, he assaulted the city. However, the garrison beat back the assault and launched their own counter-attack against the Mongols. The garrison force was similarly forced back into the city. The next day, the city's governor surrendered the city on Tolui's promise that the lives of the citizens would be spared. As soon as the city was handed over, however, Tolui reneged on his promise and slaughtered almost every person who surrendered, in a massacre possibly on a greater scale than that at Urgench. After finishing off Merv, Tolui headed westwards, attacking the cities of Nishapur and Herat. Nishapur fell after only three days, here, Tokuchar, a son-in-law of Ghengis was killed in battle and Tolui put every living thing in city, including the cats and dogs, to the sword with Tokuchars widow presiding over the slaughter.. After Nishapur's fall, Herat surrendered without a fight and was spared. Bamian in the Hindukush was another scene of carnage, here stiff resistance resulted in the death of a grandson of Ghengis. Next were the cities of Toos and Mashad. By spring 1221, the province of Khurasan was under complete Mongol rule. Leaving garrison forces behind him, Tolui headed back east to rejoin his father.

The Final Campaign and Aftermath

After the Mongol campaign in Khurasan, the majority of the Shah's army was broken. Jalal Al-Din, who took power after his father's death, began assembling the remnants of the Khwarezmid army in the south, in the area of Afghanistan. Genghis had dispatched forces to hunt down the gathering army under Jalal Al-Din, and the two sides met in the spring of 1221 at the town of Parwan. The engagement was a humiliating defeat for the Mongol forces. Enraged, Genghis headed south himself, and defeated Jalal Al-Din on the Indus River. Jalal Al-Din, defeated, fled to India. Genghis spent some time on the southern shore of the Indus searching for the new Shah, but failed to find him. The Khan returned northwards, content to leave the Shah in India.

After the remaining centers of resistance were destroyed, Genghis returned to Mongolia, leaving Mongolian garrison troops behind. The destruction and absorption of the Khwarezmid Empire would prove to be a sign of things to come for the Islamic world, as well as Eastern Europe. The new territory proved to be an important stepping stone for Mongol armies under the reign of Genghis' son Ögedei to invade Kievan Rus' and Poland, and future campaigns brought Mongol arms to Austria, the Baltic Sea and Germany. For the Islamic world, the destruction of Khwarezmid left Iraq, Turkey and Syria wide open. All three were eventually subjugated by future Khans.

The war with Khwarezmid also brought up the important question of succession. Genghis was not young when the war began, and he had four sons, all of whom were fierce warriors and each with their own loyal followers. Such sibling rivalry almost came to a head during the siege of Urgench, and Genghis was forced to rely on his third son, Ögedei, to finish the battle. Following the destruction of Urgench, Genghis officially selected Ögedei to be successor, as well as establishing that future Khans would come from direct descendants of previous rulers. Despite this establishment, the four sons would eventually come to blows, and those blows showed the instability of the Khanate that Genghis had created.

Jochi never forgave his father, and essentially withdrew from further Mongol wars, into the north, where he refused to come to his father when he was ordered to. Indeed, at the time of his death, the Khan was contemplating a march on his rebellious son. The bitterness that came from this transmitted to his sons, and especially grandsons, Batu and Berke Khan, (of the Golden Horde) who would conquer Kiev Rus, and the Russian States, brought open warfare to the empire, and its fall. When the Mamluks of Egypt managed to inflict one of history's more significant defeats on the Mongols at the Battle of Ain Jalut in 1260, Hulegu Khan, one of Genghis Khan's grandsons by his son Tolui, who had sacked Bagdad in 1258, was unable to avenge that defeat when Berke Khan, his cousin, (who had converted to Islam) attacked him in the Transcaucus to aid the cause of Islam, and Mongol battled Mongol for the first time. The seeds of that battle began in the war with Khwarezmid when their fathers struggled for supremacy.

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