The Song States: Unification, Northern Losses and Southern Survival, 960–1279

The Song dynasty ruled from 960 to 1279, but not throughout that period from the same territory or political centre. Its first phase, the Northern Song, reunited much of China after the divisions of the Five Dynasties and Ten Kingdoms period, while facing powerful neighbours to the north and northwest. After the Jurchen Jin captured the Northern Song capital in 1127, the surviving court established itself farther south. This Southern Song state defended a different set of frontiers and relied more heavily on river and naval forces before the Mongols conquered it in 1279. The changing map shaped diplomacy, military spending and the movement of people.

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Reunification created a state with contested borders

The Song began in 960, when Zhao Kuangyin, later Emperor Taizu, took the throne of the Later Zhou. Song rulers then brought several states in the south under their control. Wu-Yue submitted in 978, and the Northern Han was defeated in 979. These campaigns reunited much of the territory that had been politically divided, but they did not restore control over every northern region claimed by the Song.

The Sixteen Prefectures, a strategically important area north of the Song frontier, remained under the Khitan-led Liao Empire. Song campaigns to capture the region failed, including an expedition in 979 and another in 986. The Liao therefore remained a major power on the Northern Song’s northern border. The Song state was unified in much of its territory, but it was not the only empire claiming authority in the region.

Song rulers also concentrated authority in the central government. The court staffed its administration with civilian scholar-officials and replaced regional military governors and their supporters with officials appointed from the centre. This strengthened the emperor’s reach across the reunited territories, while the divided political landscape continued to require negotiation and military defence at the frontiers.

Diplomacy and warfare on the northern and western frontiers

Song relations with the Liao shifted between conflict and negotiated coexistence. In 1004, Liao forces advanced deep into Song territory and reached Shanyuan, north of the Song capital, Kaifeng. The resulting Treaty of Shanyuan, concluded in 1005, fixed the border as it had stood before the conflict and required the Song to make annual payments to the Liao. The agreement treated the two rulers as equals in diplomatic terms. It did not end their separate political rivalry, but it established a more stable arrangement on a frontier where neither side had achieved all its aims.

Defence remained an issue. Between 993 and 1004, the Song constructed a system of canals in Hebei known as the Great Ditch, intended to hinder the advance of Liao cavalry. The Liao viewed the works with suspicion, and the Song’s frontier policies continued to prompt debate at court. Relations also combined diplomatic payments with trade, so formal agreements did not mean that contact between the neighbouring states stopped.

Farther west, the Song faced the Tangut-led Western Xia. Its ruler Li Yuanhao declared himself emperor in 1038 and rejected the former tributary relationship with the Song. War followed, imposing heavy military and financial costs. A settlement in 1044 ended this phase of fighting, with the Western Xia ruler accepting a subordinate form of address in dealings with the Song. The Song maintained garrisons across a broad western frontier, where it could not rely on the same kind of waterway barrier used against Liao cavalry in Hebei.

Song policy also caused conflict on its southern border with Đại Việt, ruled by the Lý dynasty. Disputes over frontier administration and local allegiances contributed to war in 1075–1077. The fighting ended through negotiation rather than Song conquest. In 1082 the two sides began exchanging territories and prisoners, and further talks in 1084 fixed a border between them. The episode showed how policies aimed at extending Song authority along a frontier could provoke a neighbouring state and lead to a negotiated boundary.

The fall of the Northern Song and the move south

The balance of power changed when the Jurchens, previously subject to the Liao, established the Jin dynasty in 1115. The Song allied with the Jurchens against the Liao, hoping to recover the Sixteen Prefectures. Song forces performed poorly in the joint campaigns of 1121–1123, while the Jin defeated the Liao. The alliance had helped remove one rival, but it also exposed Song military weaknesses to a new and powerful neighbour.

Jin forces turned against the Song and captured Kaifeng in 1127. The last Northern Song emperor, Qinzong, and members of the court were taken north. A surviving prince, Gaozong, was proclaimed emperor, and the court withdrew south. The capture of the capital and the loss of the northern territories ended the Northern Song period. The dynasty continued, but with a smaller territory and a different strategic centre.

Gaozong began his reign at the Song southern capital, Nanjing or Yingtian, now Shangqiu in Henan. The court later moved through several places, including Jiankang, modern Nanjing, before settling at Hangzhou, known as Lin’an. Hangzhou became its lasting seat in 1138. Refugees also moved south, enlarging cities and bringing households, skills and northern traditions into new settings.

The change in borders left the area between the Yangzi and Huai rivers exposed to raids and fighting. The Song government encouraged the resettlement of landless people from southern provinces in parts of this region. Such policies could help repopulate the borderland, but the area remained vulnerable to conflict between Song and Jin forces.

Defending the Southern Song frontier

From 1128 to 1141, the Huainan region between the Yangzi and Huai rivers was a contested zone. Song commanders resisted Jin advances and at times recovered territory, but the court ultimately chose a settlement. The Treaty of Shaoxing, negotiated in 1141 and confirmed in 1142, established the Huai River as the boundary and required the Song to make annual payments to the Jin. It also confirmed the loss of territory the Song had recovered during the fighting. For the Southern Song, the treaty provided a more settled frontier, though it did not end the political division.

The court’s southern position gave rivers and coastal waters a central role in defence. In 1132 the Southern Song established a permanent navy, which could operate on waterways and along the coast as well as support the defence of its territory. During a major Jin invasion in 1161, Song forces defeated Jin fleets at Tangdao off the Shandong coast and at Caishi on the Yangzi. The Treaty of Longxing, signed in 1165, restored the boundary established in 1142 and was followed by several decades of peace between the two states.

The Yangzi provided a major defensive line, with fleets moving troops and supplies between strongpoints. Border armies also had to hold crossings and approaches farther north. The Southern Song consequently used the waterways of its remaining territory both to support forces and to obstruct Jin advances.

Mongol conquest and the end of Song rule

The Mongols attacked the Jin in the early thirteenth century. The Song joined them in the campaign against the Jin, which fell in 1234. The alliance did not last. Song forces tried to recover the former capitals of Kaifeng and Luoyang, and conflict with the Mongols followed. Mongol forces advanced into Sichuan in 1236, bringing the war into the Southern Song’s western territory.

A key obstacle to further Mongol advances was Xiangyang and the neighbouring city of Fancheng, which controlled an important stretch of the Han River. From 1268 to 1273, Mongol forces blockaded the cities and strengthened their naval capacity, with advice from a Song defector. The fall of Xiangyang opened a route toward the Yangzi basin, the heart of the Southern Song state.

In 1276, Mongol forces captured Hangzhou. Members of the Song court and army continued resistance farther south, but their territory and options narrowed. The final major Song defeat came at Yamen in 1279, ending the dynasty. Over the preceding three centuries, the Song had moved from a programme of reunification to the defence of a southern state. Its borders, capitals and population had shifted under pressure from neighbouring powers, and the Mongol conquest finally ended its rule.

For the wider setting, see Song China: History, Economy and Society.