When the World Missionary Conference gathered in Edinburgh in 1910, it would have taken real optimism to identify Korea as a prospect for major Christian growth. At that point, Christians made up perhaps 1 percent of the Korean people, and the nation was under the heavy-handed occupation of Japanese authorities, who looked dimly on Western cultural intrusions.
Through the 20th century, though, Christian growth in Korea has been astonishing. At least 30 percent of South Korea's 50 million people are Christians. Some of Seoul's spectacular megachurches regularly appear in listings of the world's largest congregations; they are virtually denominations in their own right. The best known is the (Pentecostal) Yoido Full Gospel Church, which claims 850,000 members.