For three centuries from the 15th century, the north and west coast of Borneo including the island of Labuan was part of the Sultanate of Brunei. In the 18th century, Labuan attracted British interest. James Brooke acquired the island for Britain through the Treaty of Labuan with the Sultan of Brunei, Omar Ali Saifuddin II on 18 December 1846. A British naval officer, Rodney Mundy, visited Brunei with his ship HMS "Iris" to keep the Sultan in line until the British Government made a final decision to take the island and he took Pengiran Mumin to witness the island's accession to the British Crown on 24 December 1846. Some sources state that during the signing of the treaty, the Sultan had been threatened by a British navy warship ready to fire on the Sultan's palace if he refused to sign the treaty while another source says the island was ceded to Britain as a reward for assistance in combating pirates.