Emperor Wu of Liu Song (()宋武帝; 16 April 363– 26 June 422), personal name Liu Yu (), courtesy name Dexing (), childhood name Jinu (), was a statesman and strategist of Imperial China, and the founding emperor of the Chinese Liu Song dynasty. He came from a humble background, but became prominent after leading a rebellion in 408 to overthrow Huan Xuan, who had usurped the Eastern Jin throne in 403. After that point, using a mixture of political and military skills, Liu Yu gradually concentrated power in his own hands while expanding Jin's territory. In 420, he forced Emperor Gong of Jin to yield the throne to him, thus ending the Eastern Jin dynasty and establishing the Liu Song dynasty. He ruled only briefly, for two years, before dying and passing the throne to his son, Emperor Shao of Liu Song. An outstanding commander, perhaps the greatest of his era, he conquered two of the Sixteen Kingdoms and remained undefeated throughout his military career. The History of the Southern Dynasties described Liu Yu as seven chi and six cun tall (approximately .)
Early life
Liu Yu was born in 363, to his father Liu Qiao () and mother Zhao Anzong (), while they were living at Jingkou (京口, in modern Zhenjiang, Jiangsu). His great grandfather Liu Hun () was originally from Pengcheng (彭城, in modern Xuzhou, Jiangsu), before moving to Jingkou. Liu Qiao was said to be a 20th generation descendant of Han Dynasty's Prince of Chu, Liu Jiao (), a younger brother of Han's founder Emperor Gaozu of Han. Liu Qiao was a police officer, while Zhao Anzong was the daughter of a commandery governor. They had married in 360, and lived in fair poverty. Lady Zhao died immediately after giving birth to Liu Yu, and Liu Qiao, unable to take care of the child financially or otherwise, considered abandoning the child. Upon hearing this, Liu Yu's aunt, who had given birth to his cousin Liu Huaijing () less than a year ago, went to Liu Qiao's house and took Liu Yu, weaning Liu Huaijing and giving her milk to Liu Yu instead. At some point, Liu Qiao remarried, and his new wife Xiao Wenshou bore him two sons, Liu Daolian () and Liu Daogui (). Liu Yu was said to be respectful to his stepmother and treated her as his own mother.
It is not known when Liu Qiao died, but in any case, Liu Yu grew up with great ambitions and was said to be strong and brave, but he was poor and uneducated, knowing only a few characters. He maintained himself by selling straw sandals, and he liked gambling. The people in his village all looked down on him. At some point, he became an officer under the general Sun Wuzhong ().
When the magician Sun En rebelled against Jin rule in 399, Liu Yu joined the army of the general Liu Laozhi (), and he became friends with Liu Laozhi's son Liu Jingxuan (). On one occasion, he led some tens of soldiers on a scouting mission, when they suddenly encountered several thousand of Sun's soldiers. All of Liu Yu's soldiers were killed, and Liu Yu fell onto a riverbank, but he stood his position there and killed all of Sun's soldiers who dared to approach. Liu Jingxuan, meanwhile, realizing that Liu Yu had been away from camp for too long, went to try to find him, and saw him alone chasing and dispersing thousands of Sun's soldiers. He greatly praised Liu Yu.
Both because of his bravery and his friendship with Liu Jingxuan, Liu Yu rose through the ranks of Liu Laozhi's army. Liu Laozhi, at the time, was a powerful warlord who controlled modern Jiangsu and Zhejiang except for the region around the capital Jiankang. In 401, with Sun En, who had fled to Zhoushan Island in late 399, trying to launch a comeback and attacking Haiyan (海鹽, in modern Jiaxing, Zhejiang), Liu Yu fought him, winning several victories over him despite being outnumbered. However, eventually Sun En was able to regroup and head toward Jiankang, which he could not capture and was forced to withdraw from. He regrouped on a sea island. By imperial edict (probably at Liu Laozhi's wishes), Liu Yu was made the governor of Xiapei Commandery (下邳, roughly modern eastern Xuzhou, Jiangsu), and he was ordered to attack Sun En on his island. This allowed Liu Yu to win victories over Sun En. Sun En began to grow weaker and headed south on the coast, with Liu Yu following. In winter 401, Liu Yu defeated Sun En again at Haiyan, forcing Sun to flee far from the coast.