Oh. My. God.

Andrei Rublev, 1360-1430? This dude? https://en.wikipedia.org/wiki/Andrei_Rublev#/media/File:Rubl...

Yeah he's good, that's obvious. Klimt cribbed from Rublev I bet. Naturalism was never the topic. But note that Rublev didn't do much work between AD500 and AD1300. Because not born yet. This is precisely why I wrote down dates, and why I am insisting on counterexamples instead of vague generalities.