Confucianism, Taoism, and Buddhism are often referred to as the major religions in Korea. Among them, Buddhism influenced Korea in various ways, such as art, architecture, folk ethics, and political structure between the sixth century, when Buddhism was introduced in the Silla Kingdom, and the fourteenth century, marking the end of the Koryŏ dynasty. This essay will demonstrate the impact of Buddhism on the progress of building the political structure, and how important it was. The first introduction of Buddhism dates back to the 4th century, during the Three Kingdoms period. Koguryŏ was the first of the Three Kingdoms to officially adopt Buddhism in the second year of King Sosurim's reign (372). The king had a friendly relationship with the former Ch'in in northern China. Fu Chien, the powerful ruler of the former Ch'in, who supported Buddhism, sent a monk named Sundo to Koguryŏ with images and canon of the Buddha. In this year King Sosurim accepted Buddhism. In the case of Paekche, Buddhism was introduced by an Eastern Ch'in monk from southern China in the first year of the reign of King Ch'imnyu (392). Not long after Buddhism arrived in Paekche, King Asin proclaimed that people should believe in Buddhism and seek happiness (392). Buddhism had only a basic level of doctrine in Ch'in, where it distributed Buddhism to Koguryŏ and Paekche. So Buddhism was also not deeply understood in these two countries. As a result, although Buddhism was adopted early in these two countries, Buddhism could not have a profound impact on Koguryŏ and Paekche on their political structures. Although the official endorsement of Buddhism in Silla was the last among the Three Kingdoms, it was most successfully implemented in society. Indeed, the unofficial arrival of Bu...... mid-card ......hical, focused solely on the accumulation of wealth and power. This resulted in the large-scale Buddhist establishment which led to the construction of an immoderate monastery which was completely useless. Thus Buddhist monasteries influenced the whole country. This decadence was one of the factors in the fall of Koryŏ. This essay demonstrated the enormous impact of Buddhism on Silla and Koryŏ society. Silla became the most powerful Kingdom among the Three Kingdoms through Buddhism-based reform and achieved the unification of the Korean Peninsula. The Koryŏ dynasty was maintained the Hoguk Pulgyo which was the Buddhist ideology to protect its territory from foreign invasions. Considering these points, it can be said that there was a strong connection between Buddhism and the political structure between the 6th and 14th centuries on the Korean Peninsula..