I still remember my "great iron wars of the North" between the Japanese (me) and the Celts (AI) in Civ 4(?). The went on for around 100 years or so and decided the dominance of the continent. Still among the best games I ever had, despite hundreds of hours in Civ 6 since then. Side note, the japanese-celt wars ended in a nuclear exchange later on.

I have Civ III through Good Old Games, but sadly, they only provide it with the expansions included.

They do provide a readme that tells you you can play previous versions of the game by navigating to the install directory and running the particular executable you want, but they only ship the one executable. Not sure why they went to the trouble of removing the other executables.