evidence: From the 15th to 17th centuries, the whole island of Borneo was under the control of the Brunei Sultanate as a trading power1. Territory was gradually lost through wars, piracy and colonial expansion, and in 1888, Brunei became a British Protectorate2. It later turned down an opportunity to join the Federation of Malaya (with Singapore, Sarawak and Sabah), gaining full independence in 19843. Modern Brunei is based around the three pillars of Malay culture, Islam, and absolute monarchy4. The present sultan is King Hassanal Bolkiah, who represents one of the oldest continuous ruling dynasties in the world for over 600 years5. Officials are unelected (unique among ASEAN countries) with the monarch holding absolute executive and legislative powers. Brunei became the first East Asia country to adopt sharia law, first announced in 2013 and then gazetted in 2019. [...] Present-day Brunei occupies the north-west coast of Borneo. It is 5,765km2, which is roughly eight times the size of Singapore6. There are two areas, separated by the valley of the Limbang River that is part of Sarawak, Malaysia7, although they are now connected via the Temburong Bridge. The two areas comprise four districts. In the west, Brunei-Muara, Tutong and Belait contain hilly lowlands, swampland, and alluvial valleys. Temburong in the east is more mountainous, the highest peak being Bukit Pagon at 1,850m. There is 161km of coastline providing a rich tropical marine biodiversity8.