What city was a city was reffered to as a city on a hill?

That's Lisbon, capital city of Portugal. Rome is also (and perhaps firstly) described as being built on seven hills.

Rome

Whan it has a seat----------------A City is a City when it is INCORPORATED....essentially, it then becomes a Buisness It makes money through taxes (property, Sales, etc.) otherwise, an area not...

Both which and what can be used

A city is a city because it was one the the important places in the world.