Emperor Wu of the Song Dynasty Liu Yu (April 16, 363 - June 26, 422) was an outstanding politician and military strategist, and the founding emperor of the Liu Song Dynasty during the Northern and Southern Dynasties. When Liu Yu was in power, he learned the lessons of the previous dynasty's powerful Tu people who used their power to dominate the country, restrained powerful mergers, and took many measures to consolidate the throne. This also showed the entrepreneurial king's ability to govern the country.