The Huanglao Taoist school 黃老道家revived when Confucianism faced a crisis at the end of the Han dynasty. This school developed from Huanglao's logic and the theory of conserving vital power. It played a key role in criticism by society and even once became the mainstream ideology of the Cao-Wei 曹魏 era during the chaotic wars of the Jian-an 建安 reign. Nevertheless, because Confucianism was so deeply rooted in Chinese society, Huanglao Taoism was unable to fully replace it. The intellectuals were greatly concerned about the differences between Confucianism and Taoism and the most important academic dilemma was how to combine the two school of thoughts.After much effort the thinkers of the Cao-Wei period developed the early form of Neo-Taoist玄學 thought which combined Taoism and Confucianism. Huanglao's logic and the theory of conserving vital power was intermingled with Confucian ethics to respectively form the characteristics of the two Neo-Taoist schools of thought:nihilism and natural vitality. The essence of this thought transformation stemmed from the inclusion of the Confucian social ethics and the Taoist stress on individual freedom into the cultural disposition of the intellectuals of that time. This was basically completed by the last three generations (the end of the Han dynasty as well as the Jian-an and Zhengshi 正始 periods) of intellectuals as they inherited and developed the former generation's thought.