From Fantasy Flight's Website :
"The Realm is growing and so is the capital city! While the governors of the peripheral fiefs may not see it often, the King expects regular tributes to contribute to its expansion... or he could forget to send his soldiers to protect the borders"
This official scenario for "Kingsburg" implores a system for contribution to the King, as well as positive and negative outcomes depending on if you make the tithes or not. It requires the use of counters of your choice to be used as "Growth Counters" (e.g. pennies, cubes, etc...)
- Kingsburg: The Demanding Capital