According to Christian traditions, the Apostle Thomas was active in Sri Lanka as well as southern India during the first century A.D. Small Christian communities existed on the coasts of Sri Lanka during the succeeding centuries, flourishing on the edges of the Indian Ocean trade routes as Islam did in later times. Christianity made significant inroads only after the fifteenth century, as aggressive Portuguese missionary efforts led to many conversions, especially among the Karava and other low-country castes. When the Dutch took control of Sri Lanka, they encouraged their own missionaries of the Dutch Reformed Church. Under their patronage, 21 percent of the population in the low country was officially Christian by 1722. The British, in turn, allowed Anglican and other Protestant missionaries to proselytize.

The relative number of Christians in Sri Lanka has declined steadily since the end of colonial rule. In 1900 a reported 378,859 people, or 10.6 percent of the population, were officially Christians. Although in 1980, the number of Christians had increased to 1,283,600, the percentage of Christians in the total population had declined to approximately 8 percent. This decline occurred primarily because the non-Christian population expanded at a faster rate. Emigration abroad, conversions of some Christians to Buddhism and fewer conversions to Christianity among Buddhists, Hindus, or Muslims also were reasons for the decline. In the 1980s, Christians still were concentrated heavily in the low country in the southwest. They comprised 30 percent of the population in Colombo.

Some 88 percent of the Christians were Roman Catholics who traced their religious heritage directly to the Portuguese. The Roman Catholic Church has a well-established organization that encompasses the entire island. In 1985 there were 9 dioceses comprising 313 parishes, 682 priests, and 15 bishops (including two archbishops and a cardinal). The remainder of Christians were almost evenly split between the Anglican Church of Ceylon (with two dioceses) and other Protestant faiths. The Dutch Reformed Church, now the Presbytery of Ceylon, consisted mostly of Burghers, and its numbers were shrinking because of emigration. Other Christian communities--Congregationalists, Methodists, and Baptists--were small in number. Since the 1970s, there has been a movement of all Protestant Churches to join together in a united Church of Sri Lanka. The Sinhalese community, however, has strenuously opposed this movement.

Data as of October 1988