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.
