The Mongol conquest of China was a series of major military efforts by the Mongol Empire to conquer various empires that were ruling over China for 74 years (1205–1279). It included the defeat of the Jin dynasty, Western Liao, Western Xia, Tibet, the Dali Kingdom, the Southern Song, and the Eastern Xia. The Mongol Empire under Genghis Khan started the conquest with small-scale raids into Western Xia in 1205 and 1207.
In 1279, the Mongol ruler Kublai Khan formally established the Yuan dynasty in the Chinese tradition, having crushed the last Song resistance, marking the reunification of China under Mongol rule, the first time that non-Han people had ruled the entire country. It was the first time that Tibet was added to China.
Conquest of Western Xia
In the early 1200s, Temujin, soon to be known as Genghis Khan, began consolidating his power in Mongolia. Following the death of the Kerait leader Ong Khan to Temujin's emerging Mongol Empire in 1203, Kerait leader Nilqa Senggum led a small band of followers into Western Xia. However, after his adherents took to plundering the locals, Nilqa Senggum was expelled from Western Xia territory.
Using his rival Nilga Senggum's temporary refuge in Western Xia as a pretext, Temujin launched a raid against the state in 1205 in the Edsin region. The Mongols plundered border settlements and one local Western Xia noble accepted Mongol supremacy. The next year, 1206, Temujin was formally proclaimed Genghis Khan, ruler of all the Mongols. In 1207, Genghis led another raid into Western Xia, invading the Ordo region and sacking Wuhai, the main garrison along the Yellow River, before withdrawing in 1208.
In 1209, Genghis Khan undertook a larger campaign to secure the submission of Western Xia. After defeating a force led by Kao Liang-Hui outside Wuhai, Genghis captured the city and pushed up along the Yellow River, taking several cities and besieging the capital Yinchuan, which possessed a well-fortified garrison of 150,000. The Mongols were not yet experienced with siege warfare, and attempted to build a dike to divert the Yellow River and flood the city. However, the dike instead broke and flooded the Mongol camp. Emperor Li Anquan, still under threat by the Mongols and receiving no relief from the Jin dynasty, surrendered to the Mongol and demonstrated his loyalty by giving his daughter Chaka to Genghis in marriage, along with a tribute of camels, falcons, and textiles.
After their defeat in 1210, the Western Xia served as faithful Mongol vassals for the following decade, aiding the Mongols against the Jin. In 1219, Genghis Khan launched his campaign against the Khwarazmian dynasty in Central Asia, and requested military aid from Western Xia. However, the emperor and his military commander Asha refused to take part in the campaign, stating that if Genghis had too few troops to attack Khwarazm, then he had no claim to supreme power. Infuriated, Genghis swore vengeance and left to invade Khwarazm, while Western Xia attempted alliances with the Jin and Song dynasties against the Mongols.
After defeating Khwarazm in 1221, Genghis prepared his armies to punish Western Xia for their betrayal, and in 1225 he attacked with a force of approximately 180,000. After taking Khara-Khoto, the Mongols began a steady advance southward. Asha, commander of the Western Xia troops, could not afford to meet the Mongols as it would involve an exhausting westward march from the capital Yinchuan through 500 kilometers of desert, and so the Mongols steadily advanced from city to city. Enraged by Western Xia's fierce resistance, Genghis engaged the countryside in annihilative warfare and ordered his generals to systematically destroy cities and garrisons as they went. Genghis divided his army and sent general Subutai to take care of the westernmost cities, while the main force under Genghis moved east into the heart of the Western Xia Empire and took Ganzhou, which was spared destruction upon its capture due to it being the hometown of Genghis's commander Chagaan.
In August 1226, Mongol troops approached Wuwei, the second-largest city of the Western Xia empire, which surrendered without resistance in order to escape destruction. In Autumn 1226, Genghis took Liangchow, crossed the Helan Shan desert, and in November lay siege to Lingwu, a mere 30 kilometers from Yinchuan. Here, in the Battle of Yellow River, the Mongols claimed to destroy a force of 300,000 Western Xia that launched a counter-attack against them.
Genghis reached Yinchuan in 1227, laid siege to the city, and launched several offensives into Jin to prevent them from sending reinforcements to Western Xia, with one force reaching as a far as Kaifeng, the Jin capital. Yinchuan lay besieged for about six months, after which Genghis opened up peace negotiations while secretly planning to kill the emperor. During the peace negotiations, Genghis continued his military operations around the Liupan mountains near Guyuan, rejected an offer of peace from the Jin, and prepared to invade them near their border with the Song. However, in August 1227, Genghis died of a historically uncertain cause, and, in order not to jeopardize the ongoing campaign, his death was kept a secret. In September 1227, Emperor Mozhu surrendered to the Mongols and was promptly executed. The Mongols then mercilessly pillaged Yinchuan, slaughtered the city's population, plundered the imperial tombs west of the city, and completed the effective annihilation of the Western Xia state.
Conquest of Jin dynasty
One of the major goals of Genghis Khan was the conquest of the Jin dynasty, allowing the Mongols to avenge the earlier death of a Mongol Khan, gain the riches of northern China and to establish the Mongols as a major power in the East-Asian world. Genghis Khan declared war in 1211, and while Mongols were victorious in the field, they were frustrated in their efforts to take major cities. In response, Genghis and his staff studied assault of fortifications. With the help of Chinese engineers, they gradually developed the techniques to take down fortifications. This eventually made troops under the Mongols some of the most accomplished and most successful besiegers in the history of warfare.
As a result of a number of overwhelming victories in the field and a few successes in the capture of fortifications deep within China, Genghis had conquered and consolidated Jin territory as far south as the Great Wall by 1213. Jin defectors and Han Chinese conscripts were recruited into new armies formed by the Mongols as they destroyed the Jin dynasty, the Cheriks (sedentary soldiers in the Mongol military). The original Han cherik forces were created in 1216 and Liu Bolin appointed as their leading officer, and they carried out a critical role in the defeat of the Jin. For example, Han Chinese defectors led by General Liu Bolin defended Tiancheng from the Jin in 1214 while Genghis Khan was occupied back north, and the next year, Xijing fell to Liu Bolin's army. As Han troops kept defecting from the Jin to the Mongols, the size of the Han cherik forces swelled and they had to be partitioned between different units. Chalaer, Yelu Tuhua and Uyar led three cherik armies in northern China under the Mongol commander Muqali, in addition to his tamma armies in 1217–1218. Han soldiers made up the majority of Yelu Tuhua's army, while Juyin soldiers from Zhongdu made up Chalaer's army and Khitan soldiers made up Uyar's army.
The Mongols received defections from Han Chinese and Khitans while the Jin were abandoned by their own Jurchen officers. Many Han Chinese and Khitan defected to the Mongols to fight against the Jin. Two Han Chinese leaders, Shi Tianze, Liu Heima (劉黑馬, Liu Ni), and the Khitan Xiao Zhala (蕭札剌) defected and commanded 3 Tumens in the Mongol army. Liu Heima and Shi Tianze served Ogödei Khan. Liu Heima and Shi Tianxiang led armies against the Western Xia for the Mongols. There were 4 Han Tumens and 3 Khitan Tumens, with each Tumen consisting of 10,000 troops. The three Khitan Generals Shimobeidier (石抹孛迭兒), Tabuyir (塔不已兒) and Xiao Zhongxi (蕭重喜) commanded three Khitan Tumens and the four ethnic Han Generals Zhang Rou, Yan Shi, Shi Tianze, and Liu Heima commanded four Han tumens under Ogödei Khan.
The first Han armies in the Mongol army were those led by defecting individual officers. There were 1,000 ethnic Han troops each in 26 units, which made up three tumeds arranged by Ogedei Khan on a decimal system. Zhang Rong, Yan Shi and Zhang Rou led three additional tumeds which were created before 1234. The Han defectors were called the "Black Army" (黑軍) by the Mongols before 1235. A new infantry-based "New Army" (新軍) was created after the Mongols received 95,000 additional Han soldiers through conscription once the 1236 and 1241 censuses were taken after the Jin was crushed. The New Army and Black Army had hereditary officer posts like the Mongol army itself. It was such Han cherik forces that were deployed against Li Tan's revolt in 1262. Shi Tianze (Shih T'ien-tse), Zhang Rou (Chang Jou, 張柔), and Yan Shi (Yen Shih, 嚴實) and other high ranking Chinese who served in the Jin dynasty and defected to the Mongols helped build the structure for the administration of the new state. The Mongols valued physicians, craftsmen and religious clerics and ordered them to be spared from death and brought to them when cities were taken in northern China.
Interethnic marriage between ethnic Han and Jurchen became common at this time. The Han Chinese General Shi Tianze's father Shi Bingzhi (史秉直, Shih Ping-chih) was married to a Jurchen woman, while Shi Tianze was married to two Jurchen women (Mo-nien and Na-ho), a Han Chinese woman (Shi), and a Korean woman (Li), and his son Shi Gang was born to one of his Jurchen wives, all of whom were prominent in Yuan court service. Shi Gang married a woman of the Kerait, a Mongolified Turkic people and part of the "Mongol nation".
Genghis advanced with three armies into the heart of Jin territory, between the Great Wall and the Yellow River. With the help of Chenyu Liu, one of the top officers who betrayed the Jin, as well as the Southern Song, who wanted revenge on Jin, Genghis defeated the Jin forces, devastated northern China, captured numerous cities, and in 1215 besieged, captured and sacked the Jin capital of Yanjing (modern-day Beijing). However, the Jin emperor, Xuan Zong, did not surrender, but moved his capital to Kaifeng, which then fell in 1232. Emperor Aizong fled to the town of Caizhou. After this, the ethnic Han general Shi Tianze led troops to pursue Emperor Aizong as he retreated, and destroyed an 80,000-strong Jin army led by Wanyan Chengyi (完顏承裔) at Pucheng (蒲城). The Jin dynasty collapsed after the siege of Caizhou in 1234. Eastern Xia, a short-lived kingdom which declared independence from Jin in 1215, was conquered in 1233.
Conquest of Dali Kingdom
Möngke Khan dispatched Kublai to the Dali Kingdom in 1253 to outflank the Song. The Gao family dominated the court, resisted and murdered Mongol envoys. The Mongols divided their forces into three. One wing rode eastward into the Sichuan basin. The second column under Uryankhadai took a difficult way into the mountains of western Sichuan. Kublai himself headed south over the grasslands, meeting up with the first column. While Uryankhadai was galloping in along the lakeside from the north, Kublai took the capital city of Dali and spared the residents despite the slaying of his ambassadors. The Dali King Duan Xingzhi (段興智) himself defected to the Mongols, who used his troops to conquer the rest of Yunnan. The Mongols appointed King Duan Xingzhi as Maharajah and stationed a pacification commissioner there. After Kublai's departure, unrest broke out among the Black Jang (one of the main ethnic groups of the Dali kingdom). By 1256, Uryankhadai, the son of Subutai had completely pacified Yunnan. The Duan family were originally Han Chinese from Wuwei in Gansu.
The Duan family still ruled Dali relatively independently during the Yuan dynasty. Later, the Ming dynasty dissolved this kingdom.