Taken from MG Turn X's manual:
The translation more or less is like this:"Black History" in Turn A Gundam is the records of wars that were sealed away, but also has another meaning- That of the concept that all Gundam series shows, starting with Mobile Suit Gundam in 1979, exist in a single timeline. In other words,1979's Mobile Suit Gundam's UC marks the beginning of humanity's space age, and 1999's Turn A Gundam's CC is its final stage. The timelines broadcast up to that point, G's FC, Wing's AC, and X's AW, as well as 2002's Seed's CE, 2007's 00's AD, and 2011's Age's AG, and all other Gundam series to come are a part of black history as well (Gundam Build Fighters seems to be an exception). The gimmicks that made this possible are nanotechnology and black history. In real life, history is filled with numerous different perceptions and interpretations, and there are countless cases of fabrications gaining momentum and being treated as fact. In the end, it may be that people only believe what they want to believe.
For those who never heard about Black History. Black History is a part of storyline in Turn A manga.
As far as I remember, SonicSP said that gunpla manuals are reliable sources. How about the bolded ones?