Brotherhood of Steel

"'In our eyes, defeat is unacceptable because we're fighting for the future of mankind. Our rallying cry is more powerful than any weapon you could ever carry. Remember that.' - Paladin Danse"

The Brotherhood of Steel (or simply BoS) are a techno-religious faction that prioritizes the salvation and preservation of 'old world' technology. They originate from the US Army soldiers stationed at the Mariposa Military base before the war which found out about the government's plans on working on a destructive disease known as the Forced Evolutionary Virus, the effects of the virus spread nationwide responsible for the creation of advanced mutant abominations in which the Brotherhood makes it's secondary goal to destroy. After the events at Mariposa the group of soldiers and their families fled to the Lost Hills bunker and in result forming the Brotherhood of Steel with the Lost Hills bunker as their main command center.

Not too long afterwards Maxson in the Lost Hills bunker in California got in touch with Lt. Elizabeth Taggerty and convinced her to start her own chapter of the Brotherhood in Appalachia. The fate of the Brotherhood in Appalachia was that all members were killed off by the scorched plague however the Brotherhood back west Sent a team to re-establish the chapter there at ATLAS Observatory. This most likely inspired the Brotherhood to send teams out East and discover new technology there however most of the groups split from the main group out west and started their own Brotherhood Chapters with their own ideologies however most remained loyal and stuck with the codex (The Brotherhood's Law)

The Brotherhood In The Capital
After a while the Brotherhood sent a team out to the Capital Wasteland (D.C.) however as they passed through Pittsburg (The Pitt) they realized the impact of some of the atrocities caused by some of the wasteland's harshest conditions on the people of The Pitt like raiders, super mutants or even just the weather itself and they decided to use their technological superiority to aid the people living there instead of keeping the technology away from them thus starting the largest known Brotherhood Chapter on the East Coast.

Once they reached D.C. They established a base in the old Pentagon and were surprised to find a large Iron-Giant styled robot called Liberty Prime stored underneath the building. With the help from Maddison Li and The Lone Wanderer the Brotherhood accomplished getting the Robot online, something which the U.S. Government Failed to do before the war. They used Prime to their advantage in their battle against The Enclave (The Pre-War American Shadow Government) who wanted to rid the Wasteland of all irradiated beings or beings that have came in contact with radiation besides themselves (which was pretty much everyone) utilizing a water purifier. They were far more technologically superior to The Brotherhood however in the end the Brotherhood won and gave the people of the Capital free clean drinking water to all the major Settlements around the area.

However when Elder Arthur Maxson came to power the East Coast Brotherhood (which by this point had advanced airships, helicopters, a giant robot and the ability to make power armor) was repurposed and welcomed the Brotherhood Outcasts (A splinter faction of the BoS) and sent three recon teams to Boston to find some technology there. Eventually a Paladin named Paladin Danse found the readings of an extreme energy source (which was at that time The Institute or the former C.I.T.) and requested for assistance immediately. Maxson and most of the Brotherhood Crew from D.C. Came on a massive Airship called The Prydwen to bring the fight to The Institute who was now kidnapping and terrorizing the locals.