中古时代，佛教的传入带来了新的文化基因。知识和信仰体系的再造，也对当时中土的政治理论和政治实践产生了深刻的影响。佛光照耀之下，中古政治史呈现出纷繁复杂的面相，而这些面相，是我们理解中古时代知识、信仰与政治世界内在逻辑的基础。佛教对中古政治的参与，并非仅仅是特定政治人物、集团与特定僧人、寺院的互相利用，而有其自身信仰的逻辑——其对未来美好世界的期盼、对理想的世俗君主的理念，乃至对统治合法性的论述，都植根于自身的知识和思想之中。佛教将政治秩序置于一个神圣而又和谐的参照系之内，把神圣的宇宙秩序扩展到人的领域，从而赋予统治者一种类似必然性、确定性和永久性的东西。中古政治的起伏、逻辑和理念，需要回到中古去理解，回到宗教光芒笼罩下的人心去理解。

In medieval China, Buddhism brought in new cultural genes. The remaking of knowledge and belief system deeply influenced the medieval political thought and practice in China. In the Buddha light, the political history of medieval China had its complex aspects, which are of significance for us to understand the world of knowledge, religions and politics in medieval China. In addition to the interactions between particular political figures or groups between particular Buddhist monks, sects, or monasteries, Buddhism's role in political history rooted in its fundamental ideas about the secular world, including its anticipation for a good world in the future and an ideal secular ruler and its discourse of ruling legitimacy. Buddhism puts political order in a divine and harmonious frame of reference, extends the sacred order of the universe to human beings and thus bestows the rulers with some necessity, certainty and eternity. Therefore, it is necessary for us to understand the political history of medieval China by taking account of Buddhist materials and religious logics.