Sultan Abdul Momin of Brunei declared the Oath of Amanat in 1885 in an attempt to prevent further losses of Brunei's territories to foreign powers like the British and Brooke family, as Brunei had already lost significant areas including Sarawak, North Borneo, and parts of the Baram region. However, the Amanat was ineffective because it was not agreed to by the foreign powers encroaching on Brunei's lands, and Brunei lacked military strength and weapons to enforce the agreement. As a result, Brunei continued losing territories like Limbang despite the Sultan's efforts.