evidence: The Philippines opposed the newly proposed federation, claiming the eastern part of North Borneo (today the Malaysian state of Sabah) as part of its territory as a former possession of the Sultanate of Sulu.[132] The Philippine government mostly based their claim on the Sultanate of Sulu's cession agreement with the British North Borneo Company, as by now the sultanate had come under the jurisdiction of the Philippine republican administration, which therefore should inherit the Sulu former territories. The Philippine government also claimed that the heirs of the sultanate had ceded all their territorial rights to the republic.[133] [...] With the continuous opposition from Indonesia and the Philippines, the Cobbold Commission was established to discover the feeling of the native populations in northern Borneo; it found the people greatly in favour of federation, with various stipulations.[137][138] The federation was successfully achieved with the inclusion of northern Borneo through the Malaysia Agreement on 16 September 1963.[139] To this day, the area in northern Borneo is still subjected to attacks by Moro pirates since the 18th century and militant from groups such as Abu Sayyaf since 2000 in the frequent cross border attacks. During the administration of Philippine president Ferdinand Marcos, Marcos made some attempts to destabilise the state of Sabah,[140] although his plan failed and resulted in the Jabidah massacre and later the insurgency in the southern Philippines.[141][142]