Liu Song is not only the longest-standing imperial dynasty in the Southern Dynasty, but also the martial arts of its founding emperor Liu Yu and the Wenzhi of his son Emperor Wen of Song, which are outstanding among the emperors of the Southern Dynasty.
Although the martial arts of Liu Yu, the Emperor wu of the Song Dynasty, were mainly evident at the end of the Jin Dynasty, this laid the foundation for Liu Song's rule. Liu Yu was born in a humble background, and judging from the fact that he was initially a military commander and enlisted in the Northern Prefecture, that is, Liu Gaozhi's army, he belonged to a low-level scholar clan. Joining one of Jiang Zuo's strongest armies at that time laid a good foundation for his future military achievements. Huan Xuandong went down to Jiankang to take power, Liu Gaozhi was forced to commit suicide between the violations, and Liu Yu was appointed as a soldier to join the army, and made many military achievements in the attack on Sun En and Lu Xun.
In the winter of 403, Huan Xuan forced Emperor An of Jin to sit in him and establish a new dynasty, Chu. In the spring of the following year, Liu Yu, together with He Wuji, Liu Yi, Zhuge Changmin, and other former generals of the Northern Prefecture, led more than a hundred followers to revolt at Jingkou and beheaded Xuzhou to assassinate Shi Huanxiu, so he marched into Jiankang, Zhang Qi was a suspect soldier, and many of the Northern Fu generals defected to Liu Yu, so huanqian and Bian Bao's army was sent by Huan Xuan. Huan Xuanrui lost his temper and abandoned Jiankang and went west. Liu Yu and others welcomed the restoration of Emperor An, and were appointed as envoys, and the military governors of Yang and Xu and other eight prefectures, and the history of Xuzhou, who held the military power. After that, Liu Yu continued to establish meritorious service, and at the beginning of the sixth year (410) of Jin Yixi, he led an army to destroy Southern Yan and occupy the Qing and Qi prefectures; In September of the same year, Lu Xun and Xu Dao were overthrown, and in March of the following year, Jiaozhou beheaded Lu Xun, quelling the biggest rebellion in Jiangzuo against the government; In the thirteenth year of Yixi (417), after the northern expedition was destroyed, Qin entered Chang'an, and at the same time, many political enemies were destroyed. The success of the Yixi Northern Expedition also had an element of opportunity, at that time, after a long period of strife in the northern countries, most of the division veterans were tired and on the eve of reunification, Liu Yu took advantage of the void and took advantage of a lot.
In June of the fourteenth year of Yixi (418), Liu Yuliu's 12-year-old son Liu Yizhen returned to Jiankang and accepted the orders of Xiangguo, Song Gong, and Jiuxi added by Emperor An in the twelfth year of Yixi, and began the zen dynasty. Soon the generals in Guanzhong killed each other, the Jin army was defeated by Xia, and Liu Yizhen fled back alone. Therefore, when Emperor Gong of Jin ascended the throne, in the first month of the first year of Yuan Xi (419), Fang "also applied for the former order, and the duke was made king". In June of the following year, Emperor Gong of Jin issued an edict to The Song Dynasty, saying: "At the time of Huan Xuan, the Mandate of Heaven has been changed, and it will be renewed by Liu Gong for twenty years." Today's events are what the Firm is willing to do. After several "Chen Rang", Liu Yu took the throne as emperor and changed his name to Yuan Yongchu. However, he sat on the throne for less than two years, and died in May of the third year of the Yongchu Dynasty (422), passing the throne to the crown prince Liu Yifu, that is, The Young Emperor of Song.
Liu Yu's deeds were mainly before the establishment of the Song Dynasty, and his martial arts, including the re-recovery of Shu land, can be said to be the first in Jiangzuo, and because of this, he was able to replace the Jin Dynasty that lasted for a hundred years. But in order to achieve this goal, he actually gave up Guanzhong and the possibility of reunifying China. Because his confidant Liu Muzhi died of illness in Jiankang at that time, the political situation may have changed, if he lost control of the government, not only would he not be able to become the founding emperor in the future, but in the face of strong enemies such as Xia and Northern Wei, continuing the Northern Expedition or garrisoning Guanzhong would be held back and very dangerous, just as Zu Ti had encountered, so he had to miss the only opportunity in the Middle Ages to unify from south to north.
The Young Emperor Liu Yifu was the eldest son of Liu Yu, who reigned for less than two years and was obsessed with playing fun in the palace. At that time, the ministers Xu Xianzhi, Fu Liang, Xie Han, and Tan Daoji, who were under the edict of Emperor Wu, thought that he would be difficult to guard the society, so they deposed him as the King of Yingyang with the edict of the empress dowager, and soon sent him to be killed. They agreed to establish Emperor Wu's third son, Liu Yilong , the King of Yidu Commandery in Jiangling at the time, as emperor. In the autumn of 424, Liu Yilong, the emperor, took the throne as Emperor Wen of Song, and changed the year to Yuan Jia Yuan.
Whatever Xu Xianzhi's real motives were, the deposing of the emperor was itself a threat to the supremacy of imperial power. After the new emperor ascended the throne, Xu Xianzhi and they continued to rule, which not only made Emperor Wen feel a threat, but also had a power struggle with Emperor Wen's Zuochen clique at the time of the Emperor Wen's reign, so in the first month of the third year of Yuan Jia, Xu, Fu, and Xie were cursed, and although Tan Daoji had already lost his sincerity to Emperor Wen and participated in the conquest of Xie Han, and later defended the northern region with merit, he was killed 10 years later.
In addition to Emperor Wu of Liang, Emperor Wen of Song was the emperor who ruled the longest in the Southern Dynasty, so it was easier to distinguish his legacy. Because his throne was also obtained from chaos, so he paid more attention to pro-government and governance, and the history said that Yuan Jiashi "had a plan to prepare for the move, forbid the secrets of the article, punish Hengke, and there was no abuse of goods", and the reward and punishment of officials was clearly an important condition for political clarity, so the rule of Yuan Jia was superior to any other time in the Southern Dynasty, when "the town of hundreds of households, the city of yi, the song and dance, the touch of the crowd, the extreme prosperity of the Song Dynasty" was also. During this period, a major political event was the killing of Liu Yikang, the king of Pengcheng, but this matter was a power struggle in the palace and had not yet affected the overall situation.
Compared with Wenzhi, the martial arts of Emperor Wen's era were greatly inferior, and there were several Northern Expeditions, but they were not successful in the end. For example, in the seventh year of Yuan Jia, Yu Yanzhi led 50,000 troops, and Liu Yixin, the king of Changsha, and Liu Dewu, the assassin of Yuzhou, led an army of 40,000 to support the Northern Expedition, at that time, the southern army relied on boats, and the armies entered Si from Huai, but "Surabaya seeped in, and the Japanese cut ten miles." Such a slow marching ability, when encountering a highly mobile northern cavalry, can only be passively beaten. As a result, Luoyang and other places were regained and lost, and the armies were defeated and retreated, "where everything is destroyed, the house is empty." The Northern Expedition in the 27th year of Yuan Jia (450) led to the re-ignition of the war to the northern coast of the river. There are three main reasons: First, perhaps because of the lessons of the coup d'état in the middle of the Jin and Song dynasties and his own experience, Emperor Wen of Song was very tightly grasping the army, "remote control of military strategy, as for the attack on Japan and war, do not rely on the will of the order"4. The generals have lost the initiative and cannot adapt to the rapid changes in the battlefield, and it is inevitable to lose more and win less. Second, the Southern Army relies too much on boats and ships, and is greatly constrained by natural geographical conditions. There was also a lack of cavalry, and they engaged the Northern Army in North China and the Huanghuai Plain, and there were too many disadvantages. Third, it happened to encounter the Northern Wei Dynasty, which was powerful and thriving, especially the Wei Taiwu Emperor, who had outstanding military talent, and it became common to suffer losses in wars.
The fatal blow to Yuan Jiazhizhi was the southern invasion of Emperor Taiwu of Wei. Although the results of this war also greatly damaged the strength of the Northern Wei, because the battle was basically fought on the land of the Song, the local economic foundation was completely destroyed. Due to the confrontation between the north and the south, it was difficult for the social economy to recover, so that this large area of land not only failed to bring tax benefits to the southern dynasty, but even the supply of local garrisons was often difficult to support, which became one of the reasons why the southern dynasty gradually abandoned this land to the northern dynasty.