According to local historiography, Brunei was founded by Awang Alak Betatar, later to be Sultan Muhammad Shah, reigning around AD 1400. He moved from Garang in the Temburong District[19] to the Brunei River estuary, discovering Brunei. According to legend, upon landing he exclaimed, Baru nah (loosely translated as "that's it!" or "there"), from which the name "Brunei" was derived.[20] He was the first Muslim ruler of Brunei.[21] Before the rise of the Bruneian Empire under the Muslim Bolkiah dynasty, Brunei is believed to have been under Buddhist rulers.[22]
It was renamed "Barunai" in the 14th century, possibly influenced by the Sanskrit word "varuṇ" (वरुण), meaning "seafarers".[23] The word "Borneo" is of the same origin. In the country's full name, Negara Brunei Darussalam, darussalam (Arabic: دار السلام) means "abode of peace", while negara means "country" in Malay. A shortened version of the Malay official name, "Brunei Darussalam", has also entered common usage, particularly in official contexts, and is present in the United Nations Group of Experts on Geographical Names geographical database,[24] as well as the official ASEAN[25] and Commonwealth[26] listings.
The earliest recorded documentation by the West about Brunei is by an Italian known as Ludovico di Varthema. On his documentation back to 1550;
We arrived at the island of Bornei (Brunei or Borneo), which is distant from the Maluch about two hundred miles [three hundred kilometres], and we found that it was somewhat larger than the aforesaid and much lower. The people are pagans and are men of goodwill. Their colour is whiter than that of the other sort ... in this island justice is well administered ...[27]