On 4th.June, 1843 Raja James Brooke and Captain Henry Keppel organized a war expedition to attack the Dayak Iban of Saribas area. Datu Patinggi Ali who join the White Rajah in this war expedition had been sent ahead of the main tracker callled “Bala”. At the mouth of Batang Saribas he met with the seven Dayak Iban war boat called “Bangkong or Perahu Pengayau” whom Datu Patinggi Ali attacked and drove back to the up river after he succeed capturing one.
The strongest and most important Dayak Iban longhouse belonging to Orang Kaya Pemancha Dana Bayang at Nanga Padeh was about sixty miles up the Batang Saribas River and defended only by the two forts and a barrier of trees called “Pengerebah” that will block the river from being entered easily by their enemies. The longhouse was completely burnt and taken by James Brooke on the 11th.June,1843.
Three days later on the 14th.June,1843 the war expedition group of James Brooke went up to Sungai Paku, the branch of the Saribas River and attacked Linggir Mali Lebu fort at Karangan Pinggai. The Dayak Ibans did not show any resistance, but Rajah James Brooke burnt down a few longhouses along the Sungai Paku River bank.
Another three days later on the 17th.June,1843 Rajah James Brooke and his war forces went up the Sungai Rimbas another branch of the Saribas River, and attacked the fort belonging to the Dayak Iban leader by the name Rekaya Antau Linggang Nengeri and Rekaya Gun Mangku Bumi at Sungai Tawai. This was the largest and the strongest Dayak Iban fort along the Saribas River. They fought bravely but were over powered by the Armed Rajah Forces. The Rimbas chiefs then submitted. That was the first time the Dayak Ibans of Saribas River had ever fought against the White Man (Orang Putih), but not their brothers in the Skrang areas.
It was probably on 19th.August,1844 at Karangan Peris in the Skrang area that Libau RENTAP was first fought against the White Rajah armed forces. He stood bravely blocking the advance trackers of Datu Patinggi Ali’s forces with a formidable array of war boats and thousands of men on each bank of the river. They had selected a good positions where they could effectively use their spears and blowpipes.
Although the old Datu Patinggi Ali and his small contingent fearlessly fought against RENTAP and his men they were out numbered and Datu Patinggi Ali was killed along together with George Steward and twenty nine of his devoted followers with fifty six of them wounded. The main party of the White Rajah armed forces were not in time to support him.Datu Patinggi Ali and his devoted followers were buried in the Batang Undup area.