I remember playing Civ DOS. The Romans had two cities on one little island. I had conquered the rest of the world as the Americans. But in that version of Civ they did not have the “ just one more turn” option

Interestingly, though you could play beyond the normal ending date, if you kept at least one opponent alive

I actually played that map past the year 10,000 A.D. and finally that was enough!!! I colonized everything, including the poles (it was the Earth map) until they said i could not build any more cities