Quote Originally Posted by andrewt View Post
Cities are limited to 5 slots, including the settlement. Towns are limited to 3 slots. Ports do not count towards the limit.
Not entirely correct. Some towns have four slots, a minority have three. I think this may be an issue where a port counts as the fourth slot.

Likewise cities. If they have a port, they have six slots. Since we all know Rome never had a port of any sort, it has five.