Re: Filthy Rich Burghers
Mutant for Hire basically stated the definitions, except that an area which also had a cathedral was also classified as a city (up until and including the 19th century). I think there are still some places in the world where the cathedral definition still holds (but don't quote me on that.)
The very modern definition of a city has changed. I believe to be classified as a city now you need a minimum of 100,000 people. Not that long ago it was 30,000.