however, and by the late 1980s they probably had not regained their former strength. All of the Cham Muslims are Sunnis of the Shafi'i school. Po Dharma divides the Muslim Cham in Cambodia into a traditionalist branch and an orthodox branch. Christianity was introduced into Cambodia by Roman Catholic missionaries in 1660. It made little headway at first, particularly among Buddhists. In 1972 there were probably about 20,000 Christians in Cambodia, most of whom were Roman Catholics. According to Vatican statistics, in 1953, members of the Roman Catholic Church in Cambodia numbered 120,000, making it at that time the second largest religion in the country. In April 1970, just before repatriation, estimates indicate that about 50,000 Catholics were Vietnamese. Many of the Catholics remaining in Cambodia in 1972 were Europeans—chiefly French. American Protestant missionary activity increased in Cambodia, especially among some of the hill tribes and among the Cham, after the establishment of the Khmer Republic. The 1962 census, which reported 2,000 Protestants in Cambodia, remains the most recent statistic for the group. Observers reported that in 1980 there were more registered Khmer Christians among the refugees in camps in Thailand than in all of Cambodia before 1970. Kiernan notes that, until June 1980, five weekly Protestant services were held in Phnom Penh by a Khmer pastor, but that they had been reduced to a single weekly service after police harassment. There are around 21,300 Catholics in Cambodia which represents only 0.15% of the total population. There are no dioceses, but there are three territorial jurisdictions - one Apostolic Vicariate and two Apostolic Prefectures. Highland tribal groups, most with their own local religious systems, probably number fewer than 100,000 persons. The Khmer Loeu have been loosely described as animists, but most tribal groups have their own pantheon of local spirits. In general they see their world filled with various invisible spirits (often called yang), some benevolent, others malevolent. They associate spirits with rice, soil, water, fire, stones, paths, and so forth. Sorcerers or specialists in each village contact these spirits and prescribe ways to appease them. In times of crisis or change, animal sacrifices may be made to placate the anger of the spirits. Illness is often believed to be caused by evil spirits or sorcerers. Some tribes have special medicine men or shamans who treat the sick. In addition to belief in spirits, villagers believe in taboos on many