In what way is the Aztec empire prehistoric? You mean they feel old because they were primitive relative to Europe at the time? But that is known history, Europe were so far ahead technologically that they managed to conquer the whole world starting with Columbus and ending at WW2. We are living at the end of that era now, we still see the effects of Europe and its colonies dominating world politics but it is getting weaker.

I believe the parent comment means prehistoric as a technical term that means “before written history”.

The Aztecs had no written language equivalent to what we’re using here, and instead used ideographs. They did, however, record history cartographically!

Aztec script is a bit more complicated than simply ideographic. There's a whole bunch of syllabaric stuff we don't fully understand as well. Regardless, defining "prehistoric" around the presence of so-called complete writing (scripts that can represent any spoken statement) leads to a lot of really silly situations, especially in the new world. For instance, did the Aztecs suddenly become historic as soon as the Spanish showed up? If so, why didn't the Mayan script (which is also complete) count? If it's that the Aztecs who couldn't write simply weren't historic yet, does that suggest the vast majority of Europeans who also couldn't write were prehistoric?

Either way, it's a terrible definition. As an archaeologist, I use "prehistoric" to describe really old fossilized crap. Anything newer is historic.

I just meant "prehistoric" in the sense that their history is mostly lost.

That makes a lot of sense, thanks!

I meant that very little of Aztec history is recorded in a way that survives today.

My understanding - which may be wrong - is that it's at the level of much older high civilization. And I think that makes them "feel" as old as those civilizations, because we know so little.

I'm not sure the Aztecs were that technologically behind. The main reason they and all the other New World peoples lost was their less robust immune system. Typically, 80-90% of the population died of European diseases as soon as - or often even before - the Europeans arrived.

This was 300 years before germ theory, so no one on either side knew what was happening.