The CPG Massacre was an incident in the 2230s[1] where the Institute killed representatives of settlements intent on forming a 'Commonwealth Provisional Government', or CPG, ending all further attempts to form a regional government.


For some time, various settlements attempted to unite together and form a larger regional government for the Commonwealth. For four years, the Institute was also a part of this process, but began to believe that the project was falling apart due to political infighting.[4] At the behest of some divisions, the Director of the Institute chose to abandon the CPG sometime after 2187[5] and closed off all connections between the Institute and the surface.[6]


Under the supervision of the Commonwealth Minutemen,[2] multiple settlements sent representatives to a meeting to discuss the terms for the Commonwealth Provisional Government in the 2230s. However, according to Nick Valentine, the meeting was interrupted by the arrival of an Institute synth, who proceeded to attack and kill all of the representatives. Following the deaths of everyone, all negotiations effectively ceased and no further attempts at forming the CPG were made.[7][8][9]

Interestingly, the Institute appears to have suppressed knowledge of the incident. The official records mention it as an attempt to create a stable Commonwealth government gone awry.[10]


  1. 1.0 1.1 The event occurred after the Broken mask incident in 2229 and prior to the Battle of the Castle in 2240
  2. 2.0 2.1 2.2 Fallout 4 Vault Dweller's Survival Guide Collector's Edition p.517: "[18.08] THE CASTLE
    Historians have noted the original name for this settlement was Fort Independence, but the people of the Commonwealth now refer to it simply as the Castle. This place has a long and storied history; it is one of the first forts in America and predates the Revolutionary War. In recent times, it served as the base of operations for the Minutemen as they attempted (and failed) to establish a Provisional government. In 2240, the Castle was partly destroyed by gigantic Mirelurk, and most of the Minutemen leadership died.
    Still, it is generally agreed that the location could yet become an excellent base of operations for the Minutemen (and an exceptional settlement) if it can be reclaimed from the sea creatures. Note that the map information refers to interior corridors within the fortification walls."
    (Fallout 4 Vault Dweller's Survival Guide Map)
  3. CompanionNickValentine.txt/COM, Lines 391-392: Nick Valentine claims he "took up in town not long after" the CPG Massacre while the Broken Mask incident "was long before [he'd] moved to town", placing the CPG Massacre second.
  4. Director's recording #52
  5. A loading screen states "the Advanced Systems division is responsible for developing the original Molecular Relay, nearly one hundred years ago", which would place the original CPG talks four years prior to that.
  6. Fallout 4 loading screens: "After developing the Molecular Relay, an advanced teleportation device, the Institute sealed off access to the surface and began their campaign of underground expansion."
  7. CompanionNickValentine.txt/COM, Lines 387-390: Nick Valentine: "The Commonwealth Provisional Government. Years back a group of settlements tried to get together and form a coalition. Every settlement with even a hint of clout sent representatives to try and hash out an agreement. Only the Institute sent a representative of their own, a Synth. The man killed every rep at the talks. The Commonwealth Provisional Government was over before it even got off the ground. I took up in town not long after. I was damn lucky they didn't just tell me to scram right then and there."
  8. Nick Valentine: "Course, when I took up there back when, people were just as scared of the Institute as they are now, maybe more. The massacre of the CPG was still pretty fresh in people's minds at that point, and folks were still losing sleep over the Broken Mask. Plenty of people assumed I was just a saboteur, moving in to melt down the reactor or poison the drinking water. But, at the time, they couldn't exactly turn me away."
  9. Publick Occurrences: "Ever since the "Broken Mask" incident of 2229, right here in Diamond City, when the first human-looking synth infiltrated and attacked a group of innocent settlers, we have lain awake in bed at night, terrified of the Institute and everything it represents."
  10. Father: "Oh, we've tried that. Surprised? The Institute once tried to help create a stabilized Commonwealth government. It ended in bickering, infighting... it was a disaster. No, we look after our own now."
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