You should start by reading the buildings file in the base game, @Arcadian. Create your own .xml in the modding tools. Take note of things like types, buildings, building replacements, and modifiers. Modifiers are complicated abilities and should be toyed with last; subject requirements are more advanced than even these. You will aim to attach this unique building to a leader trait rather than a civilization trait.

I managed to do it by copying your artdefs. But anyway, can you tell me if you the augesteum counts as a standard temple for bonuses and requirements for other things in the game? Did you add that functionality?

I never learned, @Arcadian. You want get your hands on an invitation to the modding Discord. It seems only senior modders have such privileges.

Nice. Can you tell me how you used the default temple 3d asset? I want to make my own temple replacement for my leader but it needs a model. :)

I only use default assets to keep things from getting too complicated, @Arcadian.

Does the Augusteum have a 3d model? It's fine if it's the default temple.

Update is out.

That's interesting, @Daragh. I haven't touched this in a long time. Are you getting errors in your logs? You can find them at C:\Users\*UserName*\AppData\Local\Firaxis Games\Sid Meier's Civilization VI.

Sadly, it no longer works for me!

Outstanding!