I think it was possible for someone from then to think they knew all the knowledge in Western civilization. Even at that point though, it was far too much to ke

I think it was possible for someone from then to think they knew all the knowledge in Western civilization. Even at that point though, it was far too much to keep all in one person's head. They'd only have a surface level familiarity with most topics at best. I mean even one topic like architecture would've been impossible. You'd have to go back a lot further IMO to get it to fit. Somewhere around the development of agriculture, maybe.