Henrik Natvig Brun was born in Oslo in 1897 and received a military education. In 1921, he took over running the family farm Lunda in Uvdal. Alongside the farm work, Henrik preoccupied himself with exploring ways to better equip the Norwegian Army. He was especially interested in the idea of improving undergarments, which led him to develop a netting vest that resembles the historic Viking armour known as Brynje. Brun’s novel idea was to construct an insulating and ventilating garment that could trap warm air between the outer clothes and the skin. At first, he experimented with making vests from fishing nets but later switched to using cotton. Henrik Brun is said to have knitted over a thousand Brynje string vests himself.

For three winters, Brun was engaged by the Norwegian King’s Guard to develop cold season equipment "according to his own principles and ideas". Brun sums up an 800 km long-distance march in bad winter weather and miserable conditions, the following way: “The guardsmen were healthy and strong, far from exhausted after the march. This is probably mostly due to good clothing, good equipment and the sledge being of reasonable weight and appropriate type.” The sledge was also made by Brun.

For the first time, Brynje thermal string vests were tested by an entire field battalion. A letter addressed to Brun shows that a total of 600 vests were distributed to soldiers. The test resulted in words of praise: 1) “From random tests, which we have carried out periodically in order to accurately understand the views of the soldiers, the outcome has always been the same; that the ventilating and insulating properties of the vest fully correspond to the expectations created by the advertising." (Captain Egers, commander of the Staff Battalion) 2) “The soldiers kept warm even in the most severe conditions (- 30 degrees celsius). The reason for this was that the soldiers, in addition to their military clothing, had been given Brynje string vests. This was worn by all the soldiers and everyone seemed happy with it." (Captain Smith, commander of the 3rd Field Battery) 3) "The boys liked the Brynje string vest very much" (Captain Hellum, commander of the 4th Field Battery).

In the years following the second world war, the Norwegian Defence was looking for a manufacturer of the Brynje string vest, and at this point, the family business Jacobsen in Larvik became interested in producing "Brun’s Brynje". Brun himself lacked the proper industrial knitting machines as well as the funds to set up his own production. At the time when Brun and Jacobsen began discussing possibilities, Brun had already approached several factories without success. In the aftermath of the war, Brun had been convicted of treason for choices he made during the second world war, so the Norwegian Defence no longer wanted to conduct business with him. Jacobsen owned Raschel knitting machines, and through collaboration with both the Norwegian Army and with Brun, the Jacobsen family developed a prototype of the string vest, however, when the Armed Forces announced its first round of tender, 14 factories submitted bids. In public tenders, it is permitted to copy and make patents available to others, thus, many companies took advantage of this opportunity and in the end, it was not Jacobsen, but another manufacturer, who won the tender due to their lower production cost. Over the years, Brynje has experienced losing tenders many times - being the most affordable manufacturer is often not possible when also upholding a commitment to environmental protection, ethical principles and high-quality products.

Brynje had made people sit up. Not only in the Norwegian snow, but all over. When John Hunt planned his Everest assault, he stunned the conservative climbing community by opting for new theories like light weight, comfort and efficiency to speed up his men. All set out fully dressed in Brynje mesh, and, on the 29th of May 1953 Sir Edmund Hillary and Tenzing Norgay took us to the top of the world. – We were the first shirt up at 8850 meters and made his famous first remark our own: We nailed the bastard. Since then we’ve had numerous visits up there. Everest did wonders for the export as the Brynje became synonymous with all sorts of athletes. We even sponsored the world heavy weight champion Ingmar Johansson with a staggering $250, - and lots of shirts!

The ‘holy’ shirt became exceedingly popular while we worked on the next step. From the mid-seventies synthetic fabrics hit the market. This fitted perfectly to our mesh shirt’s philosophy. And with Super Thermo we rewrote the physics of how well a shirt could work on moisture, drying, insulation and functionality. Into the eighties more and more athletes joined us as the cyclists on the continent woke up. Their reality of sweaty uphill’s followed by ice-cold descents had been solved by plastic bags and newspapers. They now embraced our ‘holy’ (mesh) shirt. The list of Tour de France superstars that we have sent packages to is as long as the race itself.

The mesh undergarments are extremely lightweight, absorb minimal moisture and “is the most heat-insulating fibre on the market. It Insulates even better than wool when compared on an equal volume basis. In achieving this, the construction of the garment plays a major role.”

Knut Holmann took gold (K1-1000 meters) and silver (K1-10 000 meters) at the World Championships in Copenhagen in 1993 with a short-sleeved white Super Thermo mesh jersey under the singlet.

Expeditionists Harald Hauge, Cato Zahl Pedersen and Lars Ebbesen all wore Brynje’s Super Thermo Mesh as they made their way to the South Pole. Cato Zahl Pedersen became the first person with a physical handicap to ski to the South Pole and the expedition title makes reference to this. It was also the first time that fully synthetic thermal underwear was used on a polar expedition and it was found to work superbly.

Polar explorers, Sjur Mørdre and Lars Ebbesen, praised the superior performance of Brynje’s Super Thermo Mesh base layers that they wore on their expedition to the North Pole.

Brynje base layers were worn by Rolf Bae and Eirik Sønnerland as they crossed Antarctica, taking 105 days to complete what was then the world’s longest ski trek.

While wearing Brynje base layers, expeditionist Christian Eide completed a solo and unsupported trek to the South Pole in a record time of 24 days 1 hr 13 min.

At the age of 20, adventurer Teodor Glomnes Johansen became the youngest person in the world to cross Antarctica. He swears by Brynje’s Super Thermo Mesh base layers.

Wearing Brynje base layers, adventure cyclist Juan Menendez Granados became the first person in the world to cycle solo and unsupported to the South Pole. (The year prior, he cycled across Greenland.)

Frode Lein finished third in the Yukon Arctic Ultra. The Canadian race is described as the world's coldest and toughest ultra race, covering 483 kilometres and reaching extreme temperatures down to -54 degrees celsius. The 2018 race was the coldest one in its 15-year history. Frode Lein wore Brynje base, mid and shell layer clothing to stay warm and dry.

Brynje of Norway was selected to supply shell clothing to employees of the Norwegian Polar Institute, who carry out scientific research in the polar regions and advise the Norwegian government.

On 5 January 2020, 24-year-old Thomas Lone became Norway's youngest to complete The Seven Summits. Brynje is proud to have Thomas as a brand ambassador.

On 8 August 2020, 15-year-old Linn Therese Helgesen reached the top of Visbreatinden (2234 m) in the Norwegian mountain range Jotunheimen. With this, she set a historical record that will be difficult to beat! Brynje were proud to have joined Linn Therese Helgesen on her record-setting ascent.

In July 2022, Brynje opened a store in Kongens gt. 16 in Oslo