McDougall first visited Merdang in 1850, and made friends with the headman. A few years later Koch also visited Sebuyau, Sampun and Sadong. But it was not until 1862, that a priest, Zehnder, was sent to stay at Merdang. He was assisted by Thomas Dayak Webster, who was made a catechist in 1864. The first baptism in Merdang took place on Christmas Day, 1862. When Zehnder moved to Lundu in 1866, Thomas Dayak faithfully continued to look after the Christian communities at Merdang, with occasional visits from Kuching.
The most significant development came when Sharp visited Merdang in 1889. Sharp decided that the mission work in Merdang should be revived and expanded and the job was given to an ex-mission boy, Thomas Buda. Buda was subsequently made catechist in charge of Merdang. Buda started to evangelise Sebayor, Kranji, Tabuan and Stampin. He was also helped by Thomas Dayak.
A new church (St. John) was consecrated at Merdang on 29 October, 1902. Buda also started a school him self becoming a schoolmaster and was assisted by Tugang. With lay reader Lagar, Buda expanded work to Putung and Lumut. The school in Lumut was self-supporting (chicken farm and fruit orchard) and attracted students from as far as Saratok. For example, Andrew Mai from Krian was baptised there with a student in 1913.
In 1916, Buda decided to move and open a Mission centre at Taee. The school at Merdang was left in the hands of Aboi. For the next twenty years Merdang came to be looked after from either Kuap or Kuching. In most places people had lapsed to their old ways. Buda also made occasional visits on his way to Kuching. In 1938, Catechist Matthew Pauh was posted there but died shortly later and his place was taken by Lian Tetat. Tetat faithfully looked after Merdang, during the War. In 1949, , Howes visited Entinggan in response to a request for Christian instruction. Tetat undertook a catechist course in Simanggang and was posted back to Merdang in 1951. Meanwhile Andrew Kiri from Kuching, and Reuben from Kuap took turn to visit Entinggan, staying a week during each visit.
Expansion of mission work in the Samarahan area came through the visits of Miss Joan Sharman towards the end of 1952. Often accompanied by students from the House of the Epiphany, she made evangelistic visits to Stampin, Sg. Tapang, Sebayor, Rembus, and Sg. Tanju. A school had been started in Sg. Tanju in 1949. Augustine Ahim became the schoolmaster there in 1953, and was later the lay reader in 1956. In 1957, the building materials and a few furniture from the old St. Thomas’ pro-Cathedral, was moved to Sg. Tanju and used to build a new church dedicated to the Holy Cross.
In 1957, Tennant moved to Entinggan replacing Oscar Sindon. Tennant stayed there for over a year and when he moved to Simanggang, Peter Radin moved to Entinggan in 1959 and stayed until 1961. Radin continued to evangelise the villages of Lumut, Sebayur and Melaban. The church at Merdang Gayam was repaired and in 1966 a new chapel at Sg. Tapang was consecrated. After 1961 Samarahan area continued to e part of the Cathedral parish. It was only in 1985 that Samarahan area became a separate parish with the centre at St. Francis’ Church, Merdang. Chambers Saden, the present incumbent, became the first priest in charge of this new parish.