I'm at work now so can't upload the save until the weekend now, but just about everything is the same as it was 3 turns ago, other than that Isabella has gone nuts. It's not actually certain that she will attack Bagacum as there is one artillery heading for the city in the southern corner and her cavalry move so fast they could be going anywhere. There are two infantry in Bagacum now and enough cash to upgrade another 3 more grenadiers this turn.
I guess we need to weigh up the benefits of a civic change with the impact of the anarchy. 3 turns will be a long time in a battle, but then again, with no ability to rush buy, 3 turns isn't producing much anyway (as nothing much will complete building in that time). What will be the impact of 3 turns of anarchy on our cash flow?
Honestly though, if she attacks with all her artillery at once, Bagacum is doomed. Two infantry will soon be toast once they get damaged. Is there any point counterattacking with the cannons first - so that at least her stack is not at full strength? Given that cannons are not much use on defense?
Actually, now that I think about, you probably should see the exact save before deciding. This could be a real turning point in the game and there is probably one good tactic that we need to get us through.
Where is the wise and mighty Hawk when you need him?