According to official website's inquiry of China Literature and History Network, the changes of social, economic, political and cultural background and the evolution of poetry forms in the Tang Dynasty promoted the liberation of poetry from the monopoly of the court and nobles and transferred it to the intellectuals of the civilian landlords. With the reform of the political system and the implementation of the imperial examination system, intellectuals of civilian landlords have the opportunity to enter the officialdom through the imperial examination and become social elites.