Quote Originally Posted by human_male
I haven't tried a crusade yet though, and I find assassins useless. I trained a couple of them right up early on but they just get killed even when their chances are up around 70%. Now I don't even bother.
Spies and assassins can be incredibly useful in economic warfare. You use your spies to get into settlements for your assassins to see what buildings your enemies have. I rarely target something that has less than a 80% chance of success. Dump a few spies into a settlement and it causes civil unrest. This might force an enemy to lower taxes to improve public order, hence they aren't making as much money as they might otherwise. Next you use your assassins to target any buildings you can safely destroy.

If you damage a building it is unusable until they repair it. Repairing costs them money. If it's something like a cathedral or other building that grants high public order bonuses it sends their public order even lower causing them to further reduce taxes. Eventually, if you have enough assassins on sabotage missions, you can get to a point where they are constantly repairing their buildings, or causing the settlement to revolt. On top of that, a faction that has all their troop production buildings damaged has a hard time to recruit or retrain troops. A faction that loses the settlement, loses the income. As the english, if you have a force nearby, you can the swoop in, fight the rebels without having to deal with the Pope excomming you. I did this against the Danes when they were bothering me in Antwerp and Bruges, and I set them back quite a bit. It took them quite a bit to recover.

I also did this with the Pope. The Pope had taken Venice, Bologna, and had Rome. I stripped the Pope of his territories by causing them to revolt, and taking that opportunity to siege it. The Pope eventually came to me and begged for Rome back.

So, this might not improve your economics, but it can certainly give you some breathing room if it forces the enemy into financial difficulties.