At this point I have a stronghold - a small one - behind the lines. I could sit there and wait for him to attack, but my experience is that when I'm no longer the master of the ground close to the fort, they can bombard the fort until they have some holes in the walls and then my troops are trapped.

So I have chosen to attack to diminish his guns. Without guns I could withstand a stronger army in my fort.

If I loose this battle my opponent controls the half of the principality now ruled by the Hapsburgers, if I loose my fortress, then he completely gets the principality.

Without his cannons I can hold a fortified line with a stronghold in the middle.

The fortresses that I make are not 100%; I really should learn to make a Vauban fort.