From Official Wiki of the Renaissance Kingdoms

The pound is the only currency accepted in the game with which you can buy products on the market and pay various things (salaries, courses at the university, beers to the tavern, etc ...).

Note: 100 pence = 1 pounds.

It is also a special object that can be:

Possessing pounds in your inventory or in property inventory gives influence points at the rate of 1 point per 100 pounds, within the limit of 1000 points (or 100,000 pounds).