Post Classical China underwent fundamental changes which soon affected the wider world. China was one the of the core civilizations in Asia which was a network of relationships developing among Iberia and Japan as well as a influence in eastern Asia. Although China was more isolated than the Islamic world and India, it contributed vitally to other areas and flourished under the Tang dynasty.
After the end of the Zhou Empire, Li Yuan and his son Tang Taizon laid the basis for the golden age of the Tang. His armies conquered deep into central Asia and he made sure the Turks ,his greatest threat, were taken care of. His frontier units were the most powerful military in the empire and Turkic tribes were forced to become vassals to the Tang rulers ,heavenly khan. The restoration of Chinese unity was accomplished by the efforts of early Tang monarchs in rebuilding and expanding the imperial bureaucracy. The scholar-gentry elite and reworked Confucian ideology played a central role in the process. The increasing state approval for Confucian learning threatened old aristocratic families and also Buddhism monastic order, which had become a major force in Chinese life. Tang rulers continued to encourage Buddhism while trying to promote education in the Confucians classics ,though Daoist and Confucian rivals later took over as a major way of life.
After Confucianism took back it's place in Chinese life as a central ideology, it stayed so. The great influence of the new scholar-gentry in the Song era was shown in Confucian ideas and values that dominated intellectual life. Schools of philosophy went advised rival interpretation of the teachings of Confucius and wanted to prove the superiority of indigenous though systems, such as Confucianism and Daoism, over imported ones, especially Buddhism.
Between 600 and 1450, China restored it's unity by rebuilding and expanding it's imperial bureaucracy. Confucian thought was also revived and replaced Buddhism...