There are two accounts of the fight: the first, more legendary, tells of a nine-month struggle between three Brunei heroes and Bilanapura, a genie that Jerambak finally defeated using a miraculous fish skin he stole from an ogre.

The Brunei army, aided by the Dayaks, overpowered Basiung's warriors despite their superior numbers; as a result, Igan was destroyed and war spoils were taken.

[2] The Bruneian soldiers persisted in their conquests, subduing Igan's allies, such as Sarikei, Rajang, Sadung, Sarawak, Tanjung Datu, and Lingga, and stealing and capturing the traditionally Melanau regions of Oya, Matu, and Mukah.

In 1521, Antonio Pigafetta reported Brunei's military had a fleet of more than 100 boats (ships) which were involved in an attack with a faction in the south.

But despite this, they lost two battles against the Spaniards,[citation needed] after the Spaniards captured Kota Batu, Saiful Rijal changed to country's capital to Saragua (Sarawak), later they regained their strength after the Spanish force occupying the capital greatly weakened by an outbreak of cholera and dysentery.

[12] During the civil war, Abdul Hakkul Mubin fled to Kinarut (in present-day Papar, Sabah, Malaysia) where, he stayed there for ten years, repelling repeated attacks by Sultan Muhyiddin.

[12] It also noted that Muhyiddin finally defeated Abdul Hakkul Mubin in Cermin Island, by of the purchasing of gunpowder,[13] which came from Jambi Sultanate.

Sultan Omar Ali Saifuddin learned about the situation in Manila of the Philippines, due to it being Bruneian territory, he was not pleased.

Sultan Omar Ali Saifuddin signed a deal with the British Empire in June 1774 to secure outside support.

The British were looking for a storehouse along the way to Canton and received exclusive rights to the pepper trade in exchange for their military assistance.

[18] When Sulu despatch a force under the command of Datu Teting to attack Balambangan in 1775, its leaders sought safety in Labuan after the British quickly established a presence in Brunei.

[18] When the two forces clashed, Datu Teting surrendered and his troops fled back to Sulu after learning that the warriors of Brunei, led by Pengiran Temenggong Ampa, were far too strong for them to defeat.

[15] Despite Labuan's offer, the British left Brunei in 1777 due to the financial collapse of Balambangan, losing the entire East India Company.

Brunei's military was characterised by its dependence on British protection due to the kingdom's inherent limitations and the sultans' helplessness, as evidenced by the 1888 Treaty of Protection signed with Britain to preserve Brunei's geographical sovereignty, which was compromised when Brooke took control of the Limbang District in 1890, and a significant turning point occurred in 1906 when Sultan Hashim signed a Supplementary Treaty.

[23] Brunei was to gain from this approach as Britain prepared to sever its colonial connections with Malaya and northern Borneo following the Pacific War.

After being enthroned in May 1951, Sultan Omar Ali Saifuddien III started deliberations to draft Brunei's first written constitution, which included the notion of creating a military regiment.

The Brunei Malay Constitutional Advisory Committee, also known as Tujuh Serangkai, advocated for the formation of the Brunei Regiment, a Malay-led army to uphold state security and protect the reputation of the Sultan's government without depending on outside military forces, unless absolutely required and approved by the State Council and District Councils.

[24] The Sultan agreed with the Tujuh Serangkai's suggestion to create Brunei's own regiment in order to boost the country's prestige, provide palace guards, salute, and assist local law enforcement with internal security responsibilities.

Apart from that, military worries during this era led to the stationing of a Sarawak Field Force in Brunei from 1954 to 1961, which was mostly made up of Ibans and numbered around 300.

The Royal Brunei Malay Regiment established two new units, the Boat Section and the Air Service in 1965 to increase its capabilities further.

However it was common to find Bruneian pendekars to wear a jacket, a sinjang, a tanjak and shorts usually covering the knee.

They were later repelled by the Bruneian army lead by Sharif Amir who later became the caretaker of Kampong Sembulan, forcing them to retreat back to Sulu.

There is also a possibility that the Iranun and Bugis people as well may have participated due to them ruling parts of Borneo that were conquered by Brunei during Bolkiah's reign.