Why build Fortresses?

[Endoperez]

rsolow said:
2. I cannot seem to find any reason to build new fortresses. All I am building are Giants and Giant Commanders. None of the provinces I have conquered have offered me any cool units worth building (except for an occasional priest). But since I am limited to 1 commander per turn per province, resources are usually not a limitting factor so why build the fortresses? My build limits are typically in my home province and I am limitted by only being able to build 4 Holy units and by the amount of gold I have available.

In the case you missed it:
building a fort will allow you to recruit most of your national units as well. Only those that units and commanders only available from your capital's magic sites can't be recruited elsewhere. However, Jotun commanders can be very good combatants, and are both sacred and capable of blessing themselves.

If you build a temple to recruit priests, you can build a fortress as well to keep the temple safe. If an enemy takes your province, your temple will be destroyed.