@bleedingphoenix Everything past the middle ages? I think there are surviving documents, other than the Bible I don't currently have many.

I imagine it doesn't matter how far back you go, you still wont be able to rely upon summaries, Source documents will still be required, because people have agendas.

So far as I know, even very old civilization left behind writings on clay tablets. So, there should be something for you to read and learn from regardless of how far you go back.