posted 06-04-22 13:27 ET (US)   
The Caesar IV Models have a .gr2 file extension which means they were made using in Granny 3D.
There is a "Granny3D Viewer" available if you google it.
It is at https://sites.google.com/site/gr2archive/downloads
and might be an interesting tool for modders to check out and hopefully think up some new ideas of things to do.
To use the viewer
1. Create a "c:\Rome\MASTER\Data" folder on your Windows PC
2. Copy everything from your Caesar IV "Data"folder into the one created in step 1.
3. Unzip and run the viewer then open the *.gr2 files.
.
If you followed steps 1 then all the texture and colours will appears on the models. If you skipped step one then the models might not be colored correctly and turn out grey.