A brief history
A tiny country with a small population, Brunei was the only Malay state in 1963 to choose to remain a British dependency rather than join the Malaysian Federation.
It became independent in 1984 and, thanks to its large reserves of oil and gas, now has one of the highest standards of living in the world. Its ruling royals, led by the head of state Sultan Hassanal Bolkiah, possess a huge private fortune. from BBC Country Profiles
The Sultanate of Brunei's heyday occurred between the 15th and 17th centuries, when its control extended over coastal areas of northwest Borneo and the southern Philippines. Brunei subsequently entered a period of decline brought on by internal strife over royal succession, colonial expansion of European powers, and piracy.
In 1888, Brunei became a British protectorate; independence was achieved in 1984. Brunei benefits from extensive petroleum and natural gas fields, the source of one of the highest per capita GDPs in the less developed countries. The same family has ruled Brunei for over six centuries.
Source: Wikipedia, BBC, CIA - The World Fact Book