in Korea only in 1794, a decade after a Korean diplomat Yi Seung-hun(이승훈) returned to Korea. Protestant missionaries arrived in the Joseon Dynasty in 1880, and they and Catholic missionaries converted a large number of Koreans to Christianity. The Methodist Church and the Presbyterian Church established schools, hospitals, and orphanages in Korea and played an important role in the modernization of Korea. During the Japanese occupation period, Korean Christians played an important role in the struggle for independence. Factors contributing to the rapid growth of Protestants include the corrupt state of Korean Buddhism, support from intellectual elites, Korean church members' encouragement of self-reliance and self-government, and the promotion of Korean nationalism. Before the separation of the two Koreas, a large number of Christians lived in the northern part of the Korean peninsula, and the influence of Confucianism was not as strong as that in the southern part of the Korean peninsula. Before 1948 Pyongyang was an important center of the Christian faith. After the establishment of a communist regime in the north of the Korean peninsula, it is estimated that more than one million South Korean Christians fled to the south of the peninsula to escape the persecution of Christianity in North Korea. Christianity saw a huge increase in the number of people professing it in the 1970s and 1980s. Growth continued in the 1990s, but at a slow pace, with numbers declining since the beginning of the twenty-first century. Christianity is an important religion in regions including Seoul, Incheon, Gyeonggi-do, and Honam. There are four main denominations of Christianity in Korea: Presbyterian, Methodist, Baptist, and Catholic. Yeouido Full Gospel Church is the largest Pentecostal church in Korea. Korean Catholics can still keep the traditional ritual of worshipping ancestors, just like Catholics in the Chinese world; on the contrary, Protestants have completely abandoned the ritual of worshipping ancestors. Muslims There are about 40,000 followers of Islam in South Korea, most of the Muslims in South Korea are foreign migrant workers from South Asia, West Asia, Indonesia, and Malaysia to work in South Korea, and there are less than 30,000 local Korean Muslims. The largest mosque in South Korea is the Seoul Central Mosque, and there are also smaller mosques in other cities. Judaism Jews came to South Korea with the US military stationed in South Korea during the Korean War in 1950, and many Jewish American soldiers came to the