tax effectively. After the An Shi Rebellion, the Tang government monopolised salt to raise revenue; it soon accounted for over half the central government's revenues. During the reign of emperors Shi and Yi, private salt traders were executed, and the price of salt was so high that many people could not afford it. Eventually, private salt traders allied and rebelled against the Tang army. This rebellion, known as the Huang Chao Rebellion, lasted ten years and destroyed the countryside from Guangzhou to Chang'an. Following the rebellion, two generals, the Shatuo Li Keqiang and the former rebel Zhu Wen, dominated the Tang court. Civil war broke out again in the early 10th century, ending with Zhu Wen's victory. Following his victory, Zhu Wen forced the Tang emperor to abdicate, and the Tang empire disintegrated into a group of states known as the Five Dynasties and Ten Kingdoms. Five Dynasties and Ten Kingdoms period (907–960) The Five Dynasties and Ten Kingdoms was a period of warfare and disruption. After 907, the Tang government effectively disintegrated into several small states in the south, while the north saw a series of short-lived dynasties and barbarian invasions. A key event of the era was the conquest of North China by the Shatuo Turks. During their rule, the Shatuo gave the vital Sixteen Prefectures area, containing the natural geographical defences of North China and the eastern section of the Great Wall, to the Khitan, another barbarian people. This effectively left Northern China defenceless against incursions from the north, a major factor in the later fall of the Song dynasty. The Shatuo and Khitan invasions severely disrupted economic activity in the north and displaced economic activity southwards, and native Chinese rule was not restored until the Later Zhou dynasty, the Song's precursor. The southern provinces remained relatively unaffected by the collapse. The Five Dynasties and Ten Kingdoms period was largely one of continued prosperity in these regions. Late imperial era In 960, Zhao Kuangyin led a coup which established the sixth dynasty in fifty years. The Song dynasty saw a steep economic rise of China. The Late Imperial Era, encouraged by technological advancement, saw the beginnings of large-scale enterprise, waged labour and the issuing of paper money. The economy underwent large increases in manufacturing output. Overseas trade flourished under the Ming dynasty. Investment, capital, and commerce were liberalised as technology advanced and the central state weakened. Government