Not sure. Seems credible that a lot of the Renaissance era manuscripts found that are the basis of everything we know outside of architecture were forgeries. There was a big market for Roman stuff, so a lot was faked. Many have subsequently been found out, including some of Gibbons sources. But there’s forgery questions even around things like Tacitus. 

 Wow. I’d never heard that though I’m not surprised. Seems like things have taken various forms of propaganda along the way. Victors and frauds write history - that’s why Bitcoin and nostr are so important