In 1884, Horace N. Allen, an American medical doctor and Presbyterian missionary, arrived in Korea. Horace G. Underwood of the same denomination and Methodist Episcopal missionary, Henry G. Appenzeller, came from the United States the next year. They were followed by representatives of other Protestant denominations. The missionaries contributed to Korean society by rendering medical service and education as a means of disseminating their credo. Korean Protestants like Dr. So Chae’pil, Yi Sang-chae and Yun Ch’i-ho, all independence leaders, committed themselves to political causes.
The Protestant private schools, such as Yonhi and Ewha schools functioned to enhance nationalist thought among the public. The Seoul Young Men's Christian Association (YMCA) was founded in 1903 along with other such Christian organizations. The organizations carried out socio-political programs actively, encouraging the inauguration of similar groupings of young Koreans. These groups pursued not only political and educational causes but also awakened social consciousness against superstitious practices and bad habits, while promoting the equality of men and women, elimination of the concubine system, and simplification of ceremonial observances.
The ever-growing vitality of the Protestant Churches in Korea saw the inauguration of large-scale Bible study conferences in 1905. Four years later, "A Million Souls for Christ" campaign was kicked off to encourage massive new conversions to the Protestant faith. Protestantism was warmly received not only as a religious credo but also for its political, social, educational and cultural aspects.
Ch’ondogyo was initiated as a social and technological movement against rampant competition and foreign encroachment in the 1860s. At that time, it was called Tonghak (Eastern learning) in contrast to Sohak(Western learning). The principle of Ch’ondogyo is Innaech’on, which means that man is identical with "Hanulnim," the God of Ch’ondogyo, but man is not the same as God. Every man, bears "Hanulnim," the God of Ch’ondogyo in their mind and this serves as the source of his dignity,while spiritual training makes him one with the divine.