Chinese Empire

The Mongol Conquest of the Song Dynasty

The Mongol conquest of the Song dynasty was the longest, bloodiest, and most complete conquest in Chinese history, and the climactic military campaign of the Mongol world empire, the largest contiguous land empire in human history. The Mongols under Ögedei Khan invaded the Song in 1235, and the war lasted until 1279, when the last Song emperor, the child Emperor Bing, drowned at the Battle of Yamen. The campaign was fought on three fronts: the north China plain, the Sichuan basin, and the Yangzi valley. The decisive moment was the siege of Xiangyang (1268–1273), in which the Mongols, having acquired Chinese and Muslim engineers, deployed counterweighted trebuchets, gunpowder bombs, and a substantial fleet to take the previously impregnable twin cities of Xiangyang and Fancheng. The conquest established the Yuan dynasty (1271–1368), the first dynasty in Chinese history to rule the whole of China from outside the Han Chinese cultural sphere, and the topic of this piece. The longer story of the conquest see the [famous wars and conquests] section (../../), the Chinese military section, and the history of imperial China.

The Mongol conquest of the Song was the third stage of the Mongol conquest of China. The first stage was the Mongol conquest of the Jin (1211–1234), in which the Jurchen Jin dynasty, ruling north China, was destroyed. The second stage was the Mongol conquest of the Western Xia (Tangut state, 1226–1227), the Dali kingdom in Yunnan (1253), and the Karakhanids in Central Asia. The third stage was the conquest of the Song itself. Each stage drew on the resources of the previous stages, and the conquest of the Song depended critically on the Mongol acquisition of Chinese engineers, gunpowder, and naval technology.

The First Invasions (1235–1241)

The first Mongol invasion of the Song began in 1235, three years after the death of Genghis Khan and the accession of his son Ögedei as the Great Khan. The invasion was launched from three directions: from the north, across the Yellow River; from the west, through the Sichuan basin; and from the south, by way of the Yunnan corridor (after the Mongol conquest of Dali in 1253). The Mongol strategy was to encircle the Song and force it to fight on multiple fronts.

The first invasions met with mixed results. In the north, the Mongols advanced to the Yangzi, but were unable to cross it. In the west, the Mongol Sichuan campaign was a disaster. The Song, despite its military weakness, was able to put up a stubborn defence, especially in the riverine and maritime battles along the Yangzi. The Mongols were also hampered by the death of Ögedei Khan in 1241, which led to a succession crisis in the Mongol Empire and a pause in the campaign.

Khubilai Khan and the Southern Strategy (1251–1259)

The Mongol campaign resumed in the 1250s under Möngke Khan (r. 1251–1259), who pursued a more aggressive strategy. Möngke appointed his brother Kublai (later Kublai Khan, the founder of the Yuan dynasty) as the commander of the southern campaign. Kublai established his base in Shangdu (Xanadu), the summer capital of the Mongol Empire in Inner Mongolia, and began a long, methodical campaign against the Song from the north. The strategy was to bypass the Song’s riverine defences by attacking from the west, through Sichuan and Yunnan, and to isolate the Song by cutting its supply lines.

Kublai’s first campaign, in 1258, was a disaster: Möngke Khan was killed at the siege of Diaoyucheng in Sichuan, and the Mongol army was forced to withdraw. Kublai competed with his brother Ariq Böke for the title of Great Khan. Kublai won, and in 1271 he declared the establishment of the Yuan dynasty, with its capital at Khanbaliq (modern Beijing).

The Siege of Xiangyang (1268–1273)

The siege of Xiangyang (1268–1273) was the decisive campaign of the war, and one of the most important sieges in world history. The twin cities of Xiangyang and Fancheng stood on opposite banks of the Han River in modern Hubei, controlling the water and land routes between the north China plain and the Sichuan basin. The cities were heavily fortified, surrounded by walls of pounded earth and brick, with a network of outworks and a chain of signal towers. The Song garrison, commanded by General Lü Wenhu, held the cities against repeated Mongol attacks for nearly five years.

The Mongols were unable to take the cities by direct assault, and tried everything: mining, siege towers, scaling ladders, fire attacks, and flooding. The Song supplied the garrison by river and by a series of smaller forts downstream. The Mongols built a chain of forts and palisades to cut off the river supply, but the Song broke through repeatedly. The siege turned in 1271, when Kublai Khan recruited two Muslim engineers, Ala al-Din and Ismail, who designed a new generation of counterweighted trebuchets (the hui hui pao, 回回炮) capable of hurling 100-kilogram stones with much greater accuracy than the older Chinese traction trebuchets. The new trebuchets, combined with gunpowder bombs and a substantial fleet, gradually reduced the Song defences.

The Final Campaign (1274–1279)

The final campaign of the war began in 1274, with a Mongol army of perhaps 200,000 men advancing down the Yangzi. The Song army, still formidable in numbers but demoralised and poorly led, was defeated in a series of engagements. The Mongol fleet, built with the help of Chinese and Korean shipwrights, gradually gained control of the Yangzi. The Song court, under the child emperor Emperor Gong (r. 1274–1276), fled south from the capital Lin’an (modern Hangzhou). The Mongol commander Bayju took Lin’an in 1276, and the young emperor surrendered.

The war continued in the south, where loyal Song ministers raised new armies and continued to fight. The last Song emperor, the child Emperor Bing (r. 1278–1279), was carried south to Yamen (modern Xinhui, near Guangzhou) by the loyal minister Zhang Shijie. The Mongol fleet caught up with the Song fleet at Yamen in early 1279. The Battle of Yamen, fought on 19 March 1279, was the climactic naval engagement of the war. The Mongol fleet, with gunpowder bombs and counterweighted trebuchets, attacked the Song fleet in a long line. The Song fleet was defeated, and the last Song emperor, in the custody of his minister Lu Xiufu, drowned. The Battle of Yamen is sometimes called the Drowning of a Dynasty, and it is one of the most poignant episodes in Chinese history.

The Establishment of the Yuan Dynasty

The conquest of the Song in 1279 was the founding event of the Yuan dynasty (1271–1368), the first dynasty in Chinese history to rule the whole of China from outside the Han Chinese cultural sphere. The Yuan inherited the Mongol four-class hierarchy (Mongols, Semu or “various sorts,” Han, Southerners), retained Mongol military and administrative institutions, and connected China to the wider Mongol world empire. Kublai Khan’s China was the China described by Marco Polo, who visited the Yuan court in the 1280s and 1290s.

The Yuan dynasty lasted almost a century, but it was never entirely at peace. The Mongol four-class hierarchy alienated the Chinese population, the dynasty’s financial dependence on paper money produced chronic inflation, and the dynasty’s military establishment was unable to deal with the many small rebellions that broke out across the empire. The Yuan collapsed in 1368, when the rebel leader Zhu Yuanzhang (the future Hongwu Emperor of the Ming) captured Nanjing and declared the establishment of a new dynasty. The longer story of the Ming and its campaigns against the Mongols is told in the Chinese military section and the Chinese emperors section.