Questions about Siege

I am currently playing England and I have been attacked by the Spanish in Gibraltar. When they attack me it indicated I have 2 turns before I surrender. So when I attack them to break the siege. The battle starts outside of town in the wide open.

Shouldn't the enemy have to attack my fort ( as in previous Total War games )..which gives me a large advantage as a defender. Or is it because I chose to attack the sieging army. If so the game is almost forcing me to attack by indicating I will surrender in 2 turns.

Or possibly you have to build up the towns into Forts with walls...and Gibraltar is only an unprotected town at this point.

Ok, I haven't really fought siege battles in NTW. But either there are no fort fights at all (like in M2TW, ETW) or you have them once you've upgraded it more. Every siege battle I've fought, whether it was Gibraltar or any other city; I've always battled in a field, not in a fort.

ok....thank you. At least that will make it easier when I attack cities. Hope I can hold Gibraltar however. I started with a stack of 20. But looks like there are several large Spanish Armies in the area.

Ouch good luck man! I'm glad there are no fort fights; boring, slow and unnecessary. I love how action packed it is to just fight in a field like in NTW.

If you sally, it results in a normal land battle. Only if they assault do you get to fight an actual siege (with a castle).