The Bitaup are one of the 15 subgroups that inhabit the Serian/Samarahan area. Like most Bidayeh, they migrated down from Bugau, to Tembawang Tampun and finally to Tembawang Rutoi (currently Kujang Mawang).
In the 1380s, a group migrated out of Tembawang Rutoi and went to Sg. Robin. They moved up to Sg. Taup and established a village called Kampung Mawang Taup. This is the origin point for the Bitaup subgroup.
There is another alternate history passed down from generations. It’s said that the ancestors of the Bitaup is Padat, a man from Sungkung, Kalimantan who came over with his band of men in search of fruit trees and wild animals. One day, he arrived at Sg. Robin. He accidently slashed a bamboo, which fell into the river and pierced a fish. He thought it was a good omen so he settled down an established Kpg. Mawang Taup (the place where people still wear chawat).
Another legend tells of a man called Datu Merpati, from Tanjong Sipong, Santubong who desired to meet Padat and came inland to his village. While there, he fell for a local girl called Suhom. Soon she became pregnant. During her pregnancy, Merpati had to leavbe as his first wife was expecting a child. He came back after the baby was born. He changed a wooden Kelabut into stone in honour of his son, which now can be seen in Kpg. Mawang Taup. They say people used to burn the top of it in times of drought to ask for rain.
In 1940, Rev. Father Staal interview Orang Kaya Panglima Baret of Pichin. He said that he was the 19th generation after Padat, which means that at a average of 25 years per generation, the Bitaup has been living here for about 550 years.
In the late 1830s, there was an Iban Skrang attack on the people of Mawang Taup.
By the 1780s, the first group began migrating outwards and established Kpg. Sg. Ngarat, followed by the 2nd group in 1850s, Kpg. Pichin and finally Kpg. Reteh in 1927.
Most of the names of the kampungs were taken from rivers and mountains (Kuhom, Sungan). One of the major reasons for migration is congestion, lack of agricultural land and religious conflict especially with the pagans. Now most are Christians, among them Roman Catholic, Anglicanism and Seventh Day Adventists.
Slabi: Form the word terrapin (labi-labi)
Sijijag (pronounced Sejajug): Jijag trees
Munggu’ Kopi: (Hill of coffee plants) malays from Kpg. Gumpe established a Plaman for coffee planting, and when after the group from Tebakang Dayak settled there, they moved back.
Krusen Siu: Enchana led a group of people out after failing to be appointed as Orang Kaya.
Kranji: Kranji trees
Slabi Empurong: From Lubok Tempurong
Kuhom: Where boats always cpsize due to strong currents
Sebemban: Where two parallel river runs
Reteh: Named after Darud Reteh and Sungi Reteh