Throughout the ages, there have been various popular religious traditions practiced on the Korean peninsula. The oldest indigenous religion of Korea is the Korean folk religion, Korean shamanism, which has been passed down from prehistory to the present. Buddhism was introduced to Korea from China during the Three Kingdoms era in the fourth century, and the religion became an important part of the culture until the Joseon Dynasty when Confucianism was established as the state philosophy. During the Late Joseon Dynasty, in the 19th century, Christianity began to take root in Korea. While both Christianity and Buddhism would play important roles in the resistance to the Japanese occupation of Korea in the first half of the 20th century, only about 4% of Koreans were members of a religious organization in 1940.

Since the division of Korea into two sovereign states in 1945—North Korea and South Korea—religious life in the two countries has diverged, shaped by different political structures. Religion in South Korea has been characterized by a rise of Christianity and a revival of Buddhism, though the majority of South Koreans either have no religious affiliation or follow folk religions. Religion in North Korea is characterized by state atheism in which freedom of religion is nonexistent. Juche ideology, which promotes the North Korean cult of personality, is regarded by experts as a kind of national religion.

Demographics in South Korea religion1950–19621985199520052015 num. % num. % num. % num. % num. %Christianity - - 11,390,000 13,461,000 13,566,000 (Protestantism)- - 8,505,000 8,446,000 9,676,000 (Catholic church)- - 2,885,000 5,015,000 3,890,000 Buddhism- - 10,154,000 10,588,000 7,619,000 other- - - - - -non-religious- -- - - -

+ The percentage of religious beliefs by region in Korea (2015) Administrative area Korean Buddhism Protestantism Catholicism no religion or other Seoul Busan Daegu Incheon Gwangju Daejeon Ulsan Gyeonggi Province Gangwon Province North Chungcheong Province South Chungcheong Province North Jeolla Province South Jeolla Province North Gyeongsang Province South Gyeongsang Province Jeju Special Self-Governing Province Korea National

+ Korean Buddhist temples by sect (2005) Buddhist sect number of temples (%) Jogye Order () Taego Order () Beophwa Order () Zen Academy () Wonhyo Order () other

History Ancient times

Three Kingdoms of Korea period During the Three Kingdoms of Korea, foreign religions were introduced and built on the foundation of traditional Korean beliefs. Each of the three Kingdoms adopted Buddhism and Confucianism, which coexisted alongside native Korean traditional religions.

Buddhism was introduced to Korea first during the Goguryeo. In 372, the monk Sundo () was sent by Fu Jian (337–385) () of the Chinese state of Former Qin to the court of the King Sosurim of Goguryeo. He brought texts and statues (possibly of Maitreya, who was popular in Buddhism in Central Asia), and the Goguryeo royalty and their subjects quickly accepted his teachings. Additionally, it was through Goguryeo that Confucianism, a system of thought and behavior originating in ancient China, was introduced into Korea. During the reign of Sosurim, Korea established its first National Confucian Academy.

According to the Samguk sagi and Samguk yusa, the two oldest extant histories of Korea, Buddhism was officially introduced to Baekje in 384, when the Indian Buddhist monk Marananta came to Baekje from Eastern Jin. King Chimnyu welcomed him, and Baekje officially adopted Buddhism., pg. 71"Malananta bring Buddhism to Baekje" in Samguk Yusa III, Ha & Mintz translation, pp. 178-179. Both Buddhism and Confucianism flourished in Baekje, and in turn Baekje played a major role in spreading Buddhism from Korea to Japan. After striking an agreement on cultural exchanges, Japan received Confucian scholars from Baekje in the years 513 and 516.Kamata, pp. 151–155.Kamstra, pp. 232–233. Later, King Seong sent Buddhist sutras and a statue of Buddha to Japan, an event described by historian Robert Buswell as "one of the two most critical influences in the entire history of Japan, rivaled only by the nineteenth-century encounter with Western culture". The year this occurred, dated by historians to either 538 or 552, marks the official introduction of Buddhism into Japan. Within a year of this date, Baekje sent Japan nine Buddhist priests to help propagate the faith.Inoue, pp. 170–172.

Baekje continued to supply Japan with Buddhist monks for the remainder of its existence. In 587, the monk P'ungguk arrived from Baekje to serve as a tutor to Emperor Yōmei's younger brother and later settled down as the first abbot of Japan's Shitennō-ji Temple. In 595, the monk Hyeja arrived in Japan from Goguryeo.Best, pp. 31–34. He became a mentor to Prince Shōtoku and lived in Asuka Temple. By the reign of the Japanese Empress Suiko (592–628), there were over one thousand monks and nuns living in Japan, a substantial percentage of whom were Korean.

Early Buddhism in Silla developed under the influence of Goguryeo. Some monks from Goguryeo came to Silla and preached among the people, making a few converts. In 551, Hyeryang (), a Goguryeo monk, presided over the "Hundred-Seat Dharma Assembly" and the "Dharma of Eight Prohibitions". Silla formally adopted Buddhism in 527 AD after Beopheung of Silla executed Ichadon, a Buddhist convert who had tried to persuade the king to adopt Buddhism. Before he was executed, Ichadon predicted that milk colored blood would spill from his body after his death. This supposed miracle allegedly occurred according to the Samguk sagi and convinced Silla's royal court to adopt Buddhism as its state religion.

Goryeo period In the heyday of the Goryeo Dynasty, Buddhism was the state religion of Korea. A significant religious historical event of the Goryeo period was the production of the first woodblock edition of the Tripiṭaka, known as the Tripitaka Koreana. Two editions were made: the first from 1210 to 1231, and the second from 1214 to 1259. The first edition was destroyed in a fire during an attack by the Mongols in 1232, but the second edition still exists at Haeinsa in Gyeongsang Province. This edition of the Tripitaka was of high quality and served as the standard version in East Asia for almost 700 years.

Successive kings of the Goryeo dynasty exercised their supervisory powers over Buddhism and Confucianism, as well as over shamanism (). After entering the Joseon Dynasty (), the government was divided into Domu () and Jongmu (). In addition, in the east and west of the province, Hwarin-seo () were placed to accommodate the sick and the poor (), and Mugyeok () had them healed or took care of the poor. This has been the case since the Goguryeo period, with the state having Mugyeok work in state institutions.

Joseon Dynasty The Joseon dynasty ran an observatory-forecasting service called Gwangsanggam (), in which two members professionalized in myeonggwahak () were to take charge of fortune-telling.

The Joseon Dynasty initially adopted Buddhism as a religion and Confucianism as a political ideology, but gradually shifted to a policy of sungyueokbul (), in which Buddhism was suppressed in state affairs and replaced by Confucian principles. In the first half of the Joseon dynasty, Buddhist monk Hyujeong () argued that the three religions of Confucianism, Buddhism, and Taoism were in agreement with each other on fundamental levels, similar to the Three teachings. Also, there were Confucian scholars such as Maewŏltang Kim Sisŭp who sought to explain Buddhist concepts through Confucian principles.

Taoism, which has been handed down since the Goguryeo period, had Daecheong-gwan in Kaesong. After the relocation of Hanseong, Sogyeok-jeon was established, and Doryu was designated as a season, taking charge of Samcheong and Seong-jin. In addition, the worship of the Crown Prince () was transmitted to the people. As fortune-telling, secret divination, and Gam-rok spread to the civilian population, ideas such as hermitage, the last days, the rebellious revolution, and fate permeated the people deeply.

Catholicism As the Joseon dynasty entered the modern era whilst keeping the state in relative isolation, it soon faced the problem of the transmission of Western religions. Catholicism () or sometimes called seogyo () was introduced in the late 18th century as a part of Western thoughts and studies ().

Catholicism was secretly spread by missionaries infiltrating the country despite the prohibition, and it led to multiple persecutions by the court during the 19th century. This persecution was caused not only by the court's religious policy but also by actions that ran counter to Confucian ideology and Joseon policies. For example, the Hwang Sa-Yeong White Book incident, which was sparked by Catholics seeking freedom of religious belief, led to the worsening of the Sinyu Persecution () in 1801.

Donghak Due to internal and external circumstances, the court took a liberal attitude toward Western religions in 1896. This made it easy for several denominations of Protestantism to enter. Donghak emerged as a national religion amid the adversity posed by Western religions. Within two years of Donghak's emergence, it developed to the point of establishing a system of affiliates and missionaries () in various places and strengthening the denomination's organization. Eventually, it became Cheondogyo, and, under Lee Don-Hwa (), it was ideologically developed, even to the point of a philosophy of a new man.

Japanese colonial period During the Japanese colonial period, the Governor-General's Office of Korea applied the Monastery Ordinance () and the Honmuk Monastery Act () to Buddhism. The Joseon Governor-General's Decree was applied to Yurim; the Foundation Act was applied to Christianity in accordance with the Governor-General's policies; and religious organizations inherent in the Korean people were designated as similar religious organizations in addition to religion. The Governor-General's Office recognizes Shintoism, Buddhism and Christianity as religions. Chengkyunkwan of Confucianism is regarded as a school of economics, and social education law is applied to it; it is regarded as a social education institution. The Confucian temple becomes a club officer currency, and the school () is regarded as a local public body or local educational institution.

Modern Democratic People's Republic of Korea

At the time of liberation in 1945, there were about 1.5 million religious people in North Korea, 375,000 Buddhists, 200,000 Protestants, and 57,000 Catholics. There were more than 2 million religious people (22.2 percent of the population at that time). However, due to the regime's policy of stifling religion, North Korea's religious population has been greatly reduced. In a report submitted to the U.N. Human Rights Council in 2001, the North Korean regime recorded a total of 37,800 religious people, including 15,000 Chondoists, 10,000 Buddhists, 12,000 Protestants, and 800 Catholics. The number of facilities for each religion is 800, 60 temples, two churches, and one church. North Korean defectors agree that religious activities are impossible in North Korea due to the crackdown on religious activities. Religious people are subjected to human rights repression in political prison camps in the Democratic People's Republic of Korea.

Korean shamanism (Korean folk religion)

Shamanism or Folk Religion () is the oldest religious tradition in Korea, dating back as far as Old Joseon. Given its ancient origins, while Shamanism is still practiced, it is considered rather heretical and superstitious today. Shamans are typically women who are called mudang ().