The Sultanate of Brunei or simply Brunei, also known as the Bruneian Empire, was a Malay sultanate centered around Brunei on the northern coast of Borneo in Southeast Asia. Brunei became a sovereign state around the 15th century, when it substantially expanded after the fall of Malacca to the Portuguese, extending throughout coastal areas of Borneo and the Philippines, before it declined in the 17th and 18th centuries. It became a British protectorate in the 19th century.