Brunei–Indonesia relations earlier. The Nagarakretagama Javanese poem dated from 1365 CE mentioned "Barune" (Brunei) in canto 14 as one of Majapahit overseas vassal states. The relations between Brunei and the rest of Indonesian Archipelago perhaps has been established earlier during the era of Srivijayan Empire. During European colonial era, Indonesia was fell under Dutch possession as Dutch East Indies, while Brunei together with Singapore and Malaysia was fell under British Empire. In 1960s Indonesia and Brunei indirectly locked in military tension through the Konfrontasi, where Indonesia against the formation of Malaysia and dispatches troops infiltrated Sarawak, North Borneo including Brunei. Republic of
Brunei and Malaysia Brunei and Malaysia Brunei and Malaysia: " Why Sultan Omar Ali Saifuddin Refused to Join the Federation " is a 2013 book written by Isa Bin Ibrahim, a prominent member of the delegation of Sultan Omar Ali Saifuddin of Brunei with Neil Lawson QC, a London lawyer acting as the constitutional adviser on the formation of Malaysia. The book offers an inside perspective on Brunei's determination to retain its territory as an oil-rich self-governing state, contrasted with the British desire that Brunei should become part of the new federation to help counter the regional influence of China. Tunku Abdul Rahman