become Emperor Yang of Sui) to finally vanquish the Chen dynasty. Chen Shubao relied on the natural barrier of the Yangtze River and continued as always with his festive and licentious activities. The next year, Sui forces captured the Chen capital of Jiankang. Chen Shubao and his favorite concubine Zhang Lihua attempted to hide in a well but eventually were captured by Sui forces, thus ending the Chen dynasty. Culture During the Northern and Southern dynasties, the Yangtze valley transformed from a backwater frontier region with less than 25% of China's population to a major cultural center of China with 40% of China's population, and after China was subsequently unified under the Tang dynasty, they became the core area of Chinese culture. Philosophy Confucianism's unchallenged domination of Chinese culture and thought was greatly weakened during the Jin dynasty, which led to a wide diversification of political thought and philosophy by the time of the Northern and Southern dynasties. This era produced a myriad of writers that advocated practical systems of governance and administration, such as Cao Cao and Zhuge Liang in the Three Kingdoms Period, Wang Dao and Bao Jingyan of the Eastern Jin, as well as Fan Zhen, Xing Shao (), and Fan Xun () of the Northern and Southern period. Much of the philosophy of the period is despondent and dispirited, and a number of scholars and poets became reclusive mountain hermits living apart from society. Of these various trends, the most influential was Neo-Daoism (). Neo-Daoism was highly influential during the Southern Dynasty, to the point that Emperor Wen of Liu Song established a Neo-Daoist Academy and promoted it, along with Confucianism, literature, and history, as the four great subjects of study. A phenomenon known as "empty chat" () became common, where educated men would meet and talk about philosophy all day without paying any attention to "mundane" things such as their profession or family. The phenomenon gradually waned during the Sui dynasty, though it did not fully disappear until the Tang dynasty. Literature Literature was particularly vibrant during the Southern Dynasty and tended to be flowery and frilly, while Northern Dynasty literature was rougher and more straightforward. Notable writers include Yu Xin, Xing Fang, Wei Shou, and Wen Zisheng of the Northern Dynasty. In poetry, fu poetry continued to be a dominant genre, though the five-syllable form that achieved great prominence during the Tang dynasty gradually