As a Purepecha Mexican I find it very eye-opening the other way around. Very weird to see people consider our empires ancient, we are very aware we are the new kids on the block. As an aside, I have always found it interesting when people talk about the Mayans as some mythical lost thing, have had a few beers with them, good people, but not mythical by any stretch.

Go far enough and you and me share the same ancestor. I think there was a post that statistically you don't need to go that far (just a few millenia)

We need an Assyrian to chime in here...

What does contemporary mean in this context? i.e. what's not considered 'contemporary'

I mean that we don't consider them "long gone". Their teachings are as relevant today as they were at the time of their lives.

We consider Adam, Noah ancient. But the Romans? Might as well have been last week.

Well I would consider Adam and Noah to be mythologial rather than ancient.

Even Moses, who might have lived around the 13th century bc would have been 1000 years after Sargon of Akkad.

There is a lot of history to go around, so many peoples and civilisations that we know of, and so many that we do not.