How to make reward system for kingdoms (taking into account that kingdoms have very different strenght/number of players)? The reward can't be land or control of a city (cities are predefined and belong to the kingdom forever and ever). Also I don't want looting players belonging to defeated kingdom.
Example solution:
Kingdoms have prestige. If you win against a kingdom with equal/similar prestige than you you get +1 prestige and their prestige does not change. If you win against higher prestige kingdom you get +1 prestige and they lose -1 prestige. If you win against much lower prestige than yours nothing happens.