Is it fine to use the civilisations from the expansion but strictly with the core set rules? For instance one of the Arabs' abilities is for each coin that's invested, they move one space up the culture track. Of course, in the core set there is no investment card deck so that ability would be void. It's not a major one, just curious.

There's also a matter with the Greeks. One of their abilities is that they draw an extra great person card after gaining a great person and then choose between the two cards. Could they be used with just the core game where they simply collect another great person marker randomly?

I meant to say pick two great person markers at random and choose one.

The rules book says that the arabs ability is dependant on using the coin-buy system. Without that system you should not play arabs as they would be at a disadvantage.

Presumably it would work quite well having the greeks take 2 random markers and choose one instead of the cards, if you prefer playing without the cards