writings of the Jesuit missionary Matteo Ricci, who was resident at the imperial court in Beijing, had been already brought to Korea from China in the 17th century. Scholars of the Silhak ("Practical Learning"), were attracted to Catholic doctrines, and this was a key factor for the spread of the Catholic faith in the 1790s. The penetration of Western ideas and Christianity in Korea became known as Seohak ("Western Learning"). A study of 1801 found that more than half of the families that had converted to Catholicism were linked to the Silhak school. Largely because converts refused to perform Confucian ancestral rituals, the Joseon government prohibited the proselytisation of Christianity. Some Catholics were executed during the early 19th century, but the restrictive law was not strictly enforced. Protestant missionaries entered Korea during the 1880s and, along with Catholic priests, converted a remarkable number of Koreans, this time with the tacit support of the royal government. Methodist and Presbyterian missionaries were especially successful. They established schools, universities, hospitals, and orphanages and played a significant role in the modernisation of the country. During the Japanese colonial occupation, Christians were in the front ranks of the struggle for independence. Factors contributing to the growth of Catholicism and Protestantism included the decayed state of Korean Buddhism, the support of the intellectual elite, and the encouragement of self-support and self-government among members of the Korean church, and finally the identification of Christianity with Korean nationalism. A large number of Christians lived in the northern half of the peninsula (it was part of the so-called "Manchurian revival") where Confucian influence was not as strong as in the south. Before 1948, Pyongyang was an important Christian center: The city was known as the "Jerusalem of the East". Many Korean Communists came from a Christian background; Kim Il-sung's mother, Kang Pan-sok, was a Presbyterian deaconess. He attended a mission school and played the organ in church. In his memoir With the Century, he wrote: "I do not think the spirit of Christianity that preaches universal peace and harmony contradicts my idea advocating an independent life for man". In 1945, with the establishment of the communist regime in the north, however, most Christians fled to South Korea to escape persecution. Christianity came to be discouraged by the North Korean government because of its association with America. In the 1980s, North Korea produced its own translation of the Bible, which