Requirements for building Earthworks/Foundry/Great Temple/Grand Theater?

[TehJumpingJawa]

Tooltip doesn't help at all; just quoting the upper limit of the territory (1 in my case), and the cost (132.0).

I fulfil both of these requirements, so what's stopping me building?

Are they constrained by Civilization Level?
City size? (City/Metropolis)
City population?
Pre-requisite building, or tech?
Exclusive with some other type of building/holy site?

 

[Todie]

 

[Olix]

They're constrained by inventions. The invention name is shown in the tooltip, though I think you have to hover for a little while?

 

[TehJumpingJawa]

Ah!!!!
You have to hover over the number not the button.....

So the requirements are spread across two separate tooltips..... genius UI design PI, genius.

For the record I was (reasonably) expecting it on this tooltip:

 

[Rabid]

I knew that these buildings were tech limited and I still had difficulty figuring out where exactly on the UI that information was being presented.