Discuss the impact of the northern nomad peoples upon Chinese society in the late Tang and Song eras. Be specific.

The most important nomadic peoples to play an important role in Chinese history during the later Tang and Song dynasties were the Uyghurs, Liao (Khitans), and Jurchens.
The Uyghurs are a Turkic speaking people who, in the middle of the eighth century, formed their own powerful state, the Uyghur Khaganate. In 756, the Tang emperor asked the Uyghurs to help him to suppress the An Lu Shan rebellion, and the Uyghur horsemen agreed; they took part in the decisive battles and looted the capital, Luoyang. The Tang Empire had to send them tens of thousands of rolls of silk as a tribute in return. However, in the middle of the ninth century, the Uyghur state collapsed because of defeats at the hands of the Siberian Kyrgyz nomads (in 840) as well as the Tang forces (in 843).
The Liao or Khitan empire was a sinicized nomadic empire that came to include parts of Northern China during the decline of the Tang empire and the ensuing political fragmentation of the middle of the tenth century. The Khitans used the Tang model to organize their state and bureaucracy while striving to preserve their nomadic customs and military effectiveness. In the early eleventh century, the Liao emperor Shengzong defeated the Song army and forced the Chinese government to pay him a large yearly tribute in silk and silver.
In the early twelfth century, the Jurchens destroyed the Liao Empire and founded their own Jin dynasty. Many Khitans moved to Central Asia, where they defeated the Seljuks and formed their own Western Liao empire (the Kara Khitai state), which in 1216 succumbed to Mongol attack. Meanwhile, the Jurchen sinicized the nomadic Jin Empire, which gradually came to include all of Northern China. The Song dynasty retained control only over Southern China.
The Jurchen emperor Shizong received a Chinese education, but he also promoted the development of Jurchen culture and learning. In 1164 he concluded a peace treaty with the Southern Song dynasty. While in 1207 Jurchens successfully defeated a Song invasion, they could not protect their country from Mongol attack from the North (1211–1234). In 1234, the Mongol armies conquered the Jurchen state.