Buddhism was first introduced to Korea from China in 372 AD during Korea's Three Kingdoms Period, which lasted from 57 BC until 667 AD. Over time, Buddhism in Korea blended with Korean Shamanism and became Korean Buddhism as it is today. While Korean Buddhism kept the fundamental teaching of Buddha intact it adopted, it accepted and absorbed the Korean Shamanism belief of the three spirits of Sanshin, Toksong and Chilsong and there are special shrine for these spirits in many Buddhist temples. Many Buddhist temples are Korea are also built on mountains since Korean Shamanism believed they were where spirits lived, which the Buddhist also accepted. Buddhism was the state ideology under the Goryeo Kingdom (918-1392) but was very suppressed under the Joseon Dynasty (1392-1910). During the Japanese occupation of Korea (1910-1945) the Japanese uplifted the position that Buddhism had in Korea. Since World War Two ended Korea Buddhism has regained acceptance in South Korea although there has been a major divide between married and celibate monks and much conflict between Buddhist, Christians and the Korean government. In recent decades Korea's Buddhist population has declined due to more Korean's converting to Christianity or becoming atheist or unaffiliated with a religion.
Protestant Christianity was first briefly introduced to South Korea in 1832 by German Protestant missionary Karl Gutzlaff (1803-1851), but it was the second Protestant missionary to ever visit the country, Welshman Robert Jermani Thomas (1839-1866), who had a lasting impact that still is felt today. Thomas worked as a interpreter on the American schooner General Sherman and he handed out bibles to the locals. During the disputed General Sherman incident that happened in July of 1866, the schooner was sunk by the Koreans and Thomas is alleged to have jumped overboard during the firefight and handed out bibles to angry Koreans watching on shore before one of them executed him. The General Sherman incident was one of the major events that led to the 1871 United States expedition to Korea and eventually led to the 1882 Treaty of Amity and Trade between Korea and America, which included a clause that missionaries would be protected. In 1884 the first Protestant missionary from America, Horace Allen (1858-1932), came to the country and he and subsequent missionaries focused on educational and medical work since proselytizing was still illegal. During the Japanese occupation of Korea Catholics were involved in supporting the independence of Korea, being involved in the 1919 March First Movement, supporting the government in exile and by refusing to worship the Japanese emperor in the 1930s. Most Protestant Christians fled to South Korea from North Korea and in the decades since Protestant Christianity had grown rapidly. It is now the second most popular religion in the country, although there have been problems with more zealous member condemning and attacking non-Christians and other Christian sects.
Traditional Folk and Shamanistic Beliefs
Traditional Korean Shamanism has been around in Korea since times immemorial, dating back in prehistoric times to at least 40,000 BC. Korean Shamanism took root within ancient, long forgotten cultures. The religion has played a key role since Korean civilization developed back during the early, mythical part of the founding of Korea's first kingdom of Gojoseon by Dangun Wanggeom in 2333 BC. Before the introduction of Buddhism and Confucianism traditional Korean Shamanism was the dominant religion in Korea. Historically the religion has played a role in protecting people from attacks by evil spirits and helping to assist people to achieve health, peace and spiritual well being. It is also one of the world's oldest and longest surviving religions, having had parts of it blended into Buddhism, Confucianism and Christianity. Since Korea was liberated from Japanese occupation and split into two countries in 1945 there have been occasion attempts by South Korean leaders to eradicate the religion but these have failed.
New Folk and Shamanistic Beliefs
Choe Je-u (1824-1864) founded the Donghak Movement. The goal of Donghak was to reform Korea, revive Confucianism, and drive out Western influences. Je-u was executed in 1864 but his movement lived on, culminating in the Donghak Peasant Rebellion (1894-1895). In the years following this event the third patriarch of the Donghak movement, Son Byong-hi (1861-1922), decided to change the name of Donghak to Cheondogyo, often referred to as Cheondoism, with the goal of trying to modernize the religion and bring it into a new era. King Gojong (1852-1919), the second to last emperor of the Joseon Kingdom, even adopted the religion and helped to added Buddhist influences to it to give the religion a formal organizational hierarchy. Members of the movement mostly opposed the Japanese occupation and played a important rule in the Korean nationalist movement. Other new folk and shamanistic beliefs include Taejonggyo, a religion whose central creed is worshiping Dangun the mythical founder of Korea and Chungsanggyo, which is a religion that focuses on magical practices and the creation of a paradise on Earth.
Confucianism was first introduced into Korea from China during the Three Kingdoms period, around the same time that Buddhism was first introduced into the country. In 372 AD King Sosurim (?-384) of the Kingdom of Koguryô (37 BC-668 AD) created what may have been the first Confucian university in Korea. In the Kingdom of Silla (57 BC-935 AD) Confucianism was at first rejected and persecuted but it eventually became a force that led to the Silla Kingdom unifying Korea from 668 to 935. During the Kingdom of Goryeo Buddhism was the dominant religion but Neo-Confucianism managed to stick around, grow and give rise to new ideas. Under the Joseon Dynasty Korean Confucianism flourished, becoming the state religion and embedding its self into many aspects of Korean live. Starting in the 1700s Confucianism in Korea started to feel under attack from western influences and Christianity, which eventually culminated in the persecution of Christians during much of the 1800s. During the Japanese occupation of Japan, Confucianism was repressed in favor of promoting the Japanese religion of Shintoism and uplifting the position of Buddhism. Following the Japanese occupation the religion struggled to recover in the face of western influences and the erasing of Korean culture. Korean Confucianism has been making a recovery with young, new scholars and has been trying to reevaluate itself within a global context.
Roman Catholic Christianity
Roman Catholic Christians first made contact with Koreans in 1593 when a Portuguese Jesuit priest named Father Gregorious de Cespedes (1551-1611) arrived in Korea to proselytize among the small Japanese community living there. At the time, it was illegal to proselytize among Korean citizens themselves. During the 1600s, the Silhak school was formed as a response to the uneven balance of power in Korean society, with many Silhak scholars seeing Christianity as giving their beliefs a ideological basis and many of these scholars followed Catholicism and supported its expansion by the 1790s. It was also during the 1600s and 1700s that Roman Catholic Christianity grew in Korea as a native lay movement that developed in communal fashion, as opposed to a hierarchical structure. In 1784 Yi Sung-hun (1756-1801) established the first prayer-house in Korea in the city of Pyongyang. Throughout most of the 1800s, Catholics were persecuted and killed by the Korean government as the Joseon Dynasty did not accept the religion and saw it as being in direct conflict with Korean Confucian society. Some of the major crackdowns on the religion include the Catholic Persecutions of 1801, 1839 and 1866. Similar to the Protestant Christian community in Korea, the Roman Catholics were also involved in supporting Korean independence during the Japanese occupation. Most Roman Catholic Christians fled to South Korea from North Korea and in the decades since the religion has grown. In recent years there have been problems with more zealous member condemning and attacking non-Christians and other Christian sects.
The numbers of atheists and people unaffiliated with religion in South Korea is a tricky figure to calculate, as there is considerable overlap between the non-Christian religions in the country, and those who follow Confucianism may not be considered as following a religion, as it is often instead considered to be a philosophy. This is however little stigma or persecution attached to not being religious in South Korea since non-religious people do not fell the need to make themselves known. South Korea is following the trend of many other developed nations in that the number of people are say that they are atheist or unaffiliated with a religious is rising, particularly among young people.