TROOP MAINTENANCE COSTS
The cost of maintaining troops within a given province is based upon the total number of troops, both provincial and imperial, located within that province. The cost of maintaining provincial armies is NOT calculated separately from the cost of maintaining imperial armies. The presence of foreign troops within one of your kingdom's controlled provinces will also drive up troop maintenance costs, although not as much as if they were your troops stationed in the province.
A warning: The costs associated with "paying off" war leaders who have
mustered their troops in preparation for a raid or invasion which never takes
place can be very expensive. Troops who have mustered for a raid or invasion
expect booty...and if that booty does not come from the pillage of enemy
provinces it will come from the imperial coffers! It is almost always
advisable to carry out all raids and invasions which you have declared on a
previous turn. There will be cases when, for reasons of diplomacy, a mistake
in planning, or necessity, you will not wish to carry out a raid or invasion
you have previously prepared for. In these cases you will simply leave the
particular raid or invasion order form blank. Doing this often, however, can
quickly create a large drain on your kingdom's economy.