Guide to the United Presbyterian Church in the U.S.A. Commission on Ecumenical Mission and Relations Secretaries' Files: Thailand Mission

Presbyterian interests in Siam began in 1838 when the Reverend R.W. Orr from China visited Bangkok and strongly urged the opening of a mission there. In 1840, the Board of Foreign Missions appointed the Reverend and Mrs. W.P. Buell to Siam. They labored in Bangkok until 1843, whereupon Mrs. Buell's ill health mandated their return to the US. The mission remained vacant until the arrival of the Reverend and Mrs. Stephen Mattoon and Dr. and Mrs. Samuel House in 1847. Though the first Presbyterian Church in Siam was established in 1849, it took another ten years before the first Siamese convert was made. Government opposition to the missionaries characterized the first several years of the mission's existence. Most of this initial opposition had ceased by the mid 1850s. Following this period of initial opposition a station was established in the provincial capital of Petchaburi in 1860. In 1867, another station was opened in Chiengmai, 600 miles northwest of Bangkok. After the King of Siam issued a "Proclamation of Religious Liberty" in 1878, persecution of all foreign missionaries ceased and a period of rapid religious expansion commenced. Stations were opened at Lakawn (Lampang) in 1885, Rajaburi in 1889, Lampoon in 1891, Prae in 1893, Nan in 1894, Chiengrai in 1897, Pitsanuloke in 1899 and Sitamarat in 1900. In 1903, Kentung was established in the Shan States north of Siam. The station at Trang was opened in 1910. In 1917, Chiengrung was established; it was later incorporated with the Yunnan Mission in China.

Prior to 1922 there were two Presbyterian Missions in Siam. The North Siam Mission, often referred to as the North Laos Mission, centered around Chiangmai and became the springboard for missions that were later established in Lampang, Lampun, Chiangrai, Prae, Nan, Kentung and Chiengrung. Since it was not possible to travel between Chiangmai and Bangkok except during one season each year, the northern stations tended to work as a separate group. The South Siam Mission encompassed the stations of Pitsanuloke, Petchaburi, Rajaburi, Sitamarat and Trang. These stations became closely associated with Bangkok through personnel exchanges and through students from the provinces who attended Bangkok Christian College and Wattana Wittaya Academy. The isolation of the northern stations ended in 1922 when the railroad line reached Chiangmai, enabling the North Siam (North Laos) Mission to merge with the South Siam Mission. Thereafter the two missions were referred to as the Siam (later Thailand) Mission.

In 1932, the presbyteries of North and South Siam were released from the Synod of New York in order that they might form a national church. In 1934, the first General Assembly of the new church met in Bangkok and adopted a constitution. The name "The Church of Christ in Siam" was chosen with the hope that all Protestant bodies would become members of this autonomous national church. However, only members of the Presbyterian and American Baptist (Chinese) churches did so. Since the end of World War II, the Church of Christ in Siam has worked closely with the Presbyterian Board to continue the Church's ministry in Thailand.

The nature of the Presbyterian Church's ministry in Siam has been primarily evangelistic, educational and medical. The period of rapid religious expansion that began in the closing decades of the 19th century continued into the 20th century. Educational facilities such as Bangkok Christian College, the Harriet House school, the Wattana Wittaya Academy, the Dara Academy and the McGilvary Theological Seminary were established as part of the Church's ministry. The establishment of dispensaries and hospitals such as the McCormick Hospital and the leper asylums in Chiangmai and Seitamarat likewise accompanied the opening of every mission station.