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 now ruled in Brunei for over six centuries.