5th century, which led to the court revenues shifting to trade and the disappearance of the caste by the Chen dynasty. As landowning aristocrats were unable to convert cash from the produce of their estates, the resurgence of trade and the money-based economy forced them to break up and sell their lands to the burgeoning merchant class. Influential merchants increasingly occupied political offices, displacing the old aristocrats. On the other hand, the economic developments also drove peasants, unable to cope with inflation or to pay taxes in cash, to become mercenary soldiers, wandering through the country selling their services to the warring princes and plundering the populace. These upheavals devastated the south which eased the fall of the south to the Sui dynasty. Liu Song (420–479) Liu Song founder Liu Yu was originally a leader of the Army of the Northern Garrison () that notably won the Battle of Fei River in 383. In 404, he helped suppress Huan Xuan's rebellion, leading to his dominance over the Eastern Jin court. In order to gain popularity to take the throne he led expeditions against the Sixteen Kingdoms, capturing Shandong, Henan and, briefly, Guanzhong by 416. He gave up Guanzhong to try to take the throne. Because he believed in a prophecy saying there would be one more emperor after Emperor An, he deposed the former and, soon afterwards, his replacement, Emperor Gong in 420, ending the Eastern Jin dynasty. Even after crowning himself Emperor Wu, Liu Yu remained frugal. However, he did not care for education and trusted unsavory people. He felt that the nobility had too much power, so he tended to appoint the lower classes to government positions and gave military power to imperial kinsmen. Ironically, because the imperial kinsmen stabilized their military power and wished to gain political power, Emperor Wu was afraid they would have thoughts of usurping the throne. Thus, he also frequently killed his kinsmen. After the death of Emperor Wu, his son Emperor Shao ruled briefly before being judged incompetent and killed by government officials led by Xu Xianzhi, replacing him with Emperor Wen, a different son, who soon killed the officials who supported him. Emperor Wen's reign was a period of relative political stability because of his frugality and good government; the period was called the Reign of Yuanjia (). In 430, Emperor Wen started a number of northern expeditions against Northern Wei.