Fortifications

Fort mode is an optional (paid) game setting that is unlocked with the purchase of Jerusalem.

If the fort mode setting is turned on, you will be playing with the following fortifications rules:
 * All defenders in a region have a power bonus that corresponds to how long their faction has held that region (similar to how the new region income penalty is calculated)
 * A region that was acquired last turn: +3 power
 * A region acquired two turns ago: +6 power
 * The power bonus applies to all soldiers on the defending side, in all rounds of combat
 * The defense bonus can be canceled by a spy, if he infiltrates the fortification and 'opens a door'
 * Assign one spy to the region, along with any governors and raiders (to initiate the combat)
 * The spy will first have to successfully infiltrate the region (his probability is based on his spy stat and a spy of 10 will never fail)
 * If the spy is successful, he must then win a combat against one random defender
 * If he wins the combat, the defense bonus is canceled out for all defenders in the region and the spy escapes unharmed
 * If the spy fails to infiltrate, he will take part in the following combat