In the late year 1849 or in the early year 1850 James Brooke sent Arthur Crookshank to bulid a fort at the juction of the Batang Skrang River and the Batang Lupar Rivers. The establishment of the fort was indeed a nuisance to the Skrang peoples because its pupose was to block their passage to go to the open South China Sea.
The first officer was placed in charge of the fort at Nanga Skrang was a Malay’s by the name Sheriff Mohammed Hussain or Sherif Matusain or Sayid Mohsen, the grand father of the late Second Governor Of Sarawak, His Excellency Tun Datu Tuanku Haji Bujang bin Tuanku Othman. Shefif Matusin was originally came from Pontianak, Kalimantan Barat, Indonesia. He had fought on the side of the Sarawak Malays at Lidah Tanah in Kuching in the year 1840.He led the other Sarawak Malays leaders to see James Brooke and arranged for their surrender to the White Rajah.
The Ibans of the Lower Skrang area who submitted to the rule of James Brooke werenot pleased with the arrangement that Sayid Mohsen (Sherif Matusin) should be placed in charge of the fort (Kubu), and as a result , he was recalled to Kuching. His replacement was a young Englishman by the name William Brereton Nevertheless, Sayid Mohsen (Sherif Matusin ) was still remained to be a loyal friend of James Brooke for many yrers. He also being mentioned to be as a nurse to the White Rajah through a severe attack of smal pox in
Small pox 1853.
One of the principal Iban war leaders who did not submit to the rule of James Brooke at that time was the famouis Skrang Hero by the name Libaun RENTAP. He was said to be very daring, active, crafty , and a powerful and determined man. He dislike the establishment of the fort (kubu) to be placed at Nanga Skrang because he could no longer go out into the open South China Sea to collect salt and other essential comodities. He and his faithful followers
after that moved farther up-country to the headwaters of the Saribas and Skrang. There Libau RENTAP established a strong stockade on the mountain ridge up the Sungai Lang, the branch of the Batang Skrang River.
The fort (kubu) located at Nanga Skrang was then managed by William Brereton and then he was being supported by two of the best and the most capable Malay Chief, by the named Pengiran Matali who was a Brunei of rank and another Malay Chief by the name Abang Aing who was a Malanau from Matu at the mouth of the Batang Rajang River who came to Batang Lupar and settled with his father named Laksamana Medudin, and a Malay woman by the name of Dayang Kota.