The Brotherhood of Steel is one of the most well-known Fallout factions, as its Power Armor is often the most sought-after item in the game, and is featured in game posters and box art.
The Brotherhood of Steel has sub-factions with differing goals and ideas, but the most significant division in their organization is between the eastern and western Brotherhood. The west Brotherhood strives to preserve technology and protect it from unreliable hands, while the east Brotherhood seeks to assist wastelanders in need.
Before The Split
Roger Maxson, a solider who survived the Great War and witnessed horrible FEV experiments at West Tek, founded the Brotherhood of Steel on the basis that the United States was incapable of protecting its people. His goal was that the Brotherhood of Steel would protect people from themselves and their own ignorance.
The Brotherhood of Steel primarily focused on helping Great War survivors. However, Maxson realized that human knowledge could vanish. Instead of focusing on individuals, the Brotherhood refocused on technology, books, weapons, and more.
The Brotherhood of Steel began to split during Roger Maxson's death. The Brotherhood became isolated because it did not recruit outsiders. At this time, the Brotherhood was located on the western edge of the United States. It focused on expanding east, which was the next major step in its regional split.
Rise Of The Eastern Brotherhood
The Brotherhood of Steel, although isolated, wanted to go to the east to learn more. Owyn Lyons earned his honor by discovering a massive piece of technology that elevated him to an Elder. Liberty Prime, a massive robot created by the United States Army, was later discovered in the Capital Wasteland. However, Lyons decided that his mission was far from done in the Capital Wasteland.
Lyons and his team were cut off from the western Brotherhood due to his age, although some remained loyal to Lyons. His daughter led the eastern Brotherhood for a while before she died in battle. The next great leader, a descendant of Maxson, grew up with the eastern Brotherhood. However, as he became leader, he began to reestablish their connection with the west and its mission.
The Big Differences Between The East And West
Roger Maxson, the brotherhood of steel's founder, wanted the organization to both assist people and preserve technology. His concept came to fruition, although it was never presented in a united front. The east coast Brotherhood devoted itself to knowledge collecting, while the west side focused on information collection. Other factions such as the NCR pushed the western Brotherhood to stand apart from others.
The eastern branch was different. Lyons made the Brotherhood a place of help, charity, and open communication with Wastelanders. His kindness cost the faction territory and its relationship with the west. The east was more interested in the welfare of all humanity, as well as in killing super mutants, feral ghouls, and raiders.
The eastern Brotherhood ceased being charitable when Lyons died and Maxson became the faction leader in Fallout 4, but still set itself apart from the west. While the west hoarded technology to survive against the competition of the NCR, Mr. House, and Legion, Maxson's eastern Brotherhood sought to control technology to protect mankind.
Fallout 5 is still in its early stages of development.