Massacre of the CPG

The Commonwealth Provisional Government, or CPG, was an attempt by multiple towns to form a government within The Commonwealth.

Accounts of what exactly happened to it vary. According to Nick Valentine, when representatives of the towns met to discuss it, an Institute synth appeared and killed all of them, immediately ending all further attempts at the prospect.

However, Father and the Institute seem to tell a different story: Not only were the Institute originally responsible for the attempts at the formation of the CPG in the first place, they had been trying to get it together for four whole years before the event. According to them, the CPG was already quickly falling apart due to factional infighting and political squabbling, and the "synth massacre" was actually instigated by the delegates themselves killing each other rather than the synth, the latter simply taking the blame as having the dubious fortune of being the last one standing. This is further backed up by holotapes left over from before Father's tenure as director as well as loading screens.

In any case, the death of the CPG marked both the end of the Institute's attempt at meaningful cooperation with the surface, and the beginning of the Commonwealth's paranoia concerning synths.

Appearances
the Commonwealth Provisional Government is mentioned only in Fallout 4.