Break Siege Failure

[PsiSoldier]

Ok quick question.. If my fort is besieged and I attempt to break the siege and fail, do my units retreat back into the fort, or do they retreat to a neighboring province or do they simply die?

What is the priority for how the game handles that?


And to expand the question a little further, what also happens in the event that I script a unit to cast spells or fire a few times and then retreat? Is that handled differently and if so what happens in that case?