There are plenty of people not born in a particular location, from a particular family or from a particular ethnic group that end up contributing to a larger civilisation.

There are over 180 countries in the world with many different versions of them over 6000 years. So if you choose 18 you can expect at best only covering 10% of the worlds current nations... so Turkey is out there with the other 90%.

You can also rename your civilisation... I always used to play the romans or mongols and rename them... I am not so centric that I only play british nor do I play them in the majority.

BTW do you know which general I am referring to?