War Expenses

The cost of a war is rated in percentages of base income, and is derived from the distance the war is being fought at and the level of of a fief's commitment.

Percent Cost       Commitment Level       Description
1%                 Minor                  Very small expeditionary force.
3%                 Major                  Significant force
5%                 Full                   Vast majority of forces

The distance matters, too. For a Short Distance conflict - in the boundaries of a fief or someplace immediately adjacent - cost is above. A Medium Distance conflict (within the same region) doubles cost, and a Long Distance conflict (cross-continental) triples cost.