This dynasty is divided into two periods: Northern Song (AD960-1126) during which China was unified and Southern Song (1127-1279), when the Song ruled the south and the [G 09 / Jurchen] Jin Dynasty (1115-1234) the north. Other alien dynasties prominent during the reign of the Song were the Liao (AD904-1125), the Xixia (AD990-1227) and the [G 12 / Mongol] Yuan, which finally conquered all of China.
The first years of the Song Dynasty were those of unification and an end to the militarization that had swept through China. The Northern Song fell when its last emperor's extravagant tastes and poor judgement, combined with financial mismanagement and military ineptitude, resulted in his abdication. The Southern Song virtually abandoned the idea of retaking the north from the Jurchen and a peace treaty was signed. Song leaders at the time were not known for their all-powerful control and were open to outside influences.
Although often seen as weak, the dynasty enjoyed almost unprecedented harmony with its neighbors. Urbanization was a new social phenomenon that arose during the Song. Large cities formed and spread beyond the limited confines of the old walls. The Song was also renowned for its technological contributions that included the printing press.
The dynasty began to fall when foreign policy was reversed. In an effort to recover long-lost territory, the Song attacked its neighbors. Forty years later the Mongols overran China and the Yuan Dynasty emerged.
SONG WEAKNESS:
The Song's policies, which were far more abstract and philosophical than the Tang, made it difficult for the leaders to deal successfully with the nomads. As a result they turned their attention to the southern states as these were easier to annex than those in the north. In 1134, they ceded the territory north of the Huai River to the Jin Dynasty. The Song leader's system of buying peace from the tribes to the northeast, in addition to keeping a large army, was costly.
LIAO WALL BUILDING:
Although the Liao built walls around 1138, their achievements were minimal compared to others like the Jin who built extensively beforehand. The bulk of the Liao building took place in 1181. Further construction was completed by 1198.
Both the Liao and the Jin introduced technical innovations into their wall building. Some of the Jin walls have an outer moat and wall, as well as an inner moat and a main wall. The inner moat ranges from 33-197 feet wide. Jin walls also had beacon towers as well as semicircular platforms on the outside called `mamian' or horse faces, in addition to battlements and [G 16/parapets].
The Jin's longest walls are in Inner and Outer Mongolia. When the [G 12 / Mongols] swept across China, frontier walls were rendered useless. Not until the Mongol empire began to fall apart did wall building re-emerge in China.
