Here's a better question: what reason does SA have to declare war on Prvencia di florenza? it is even nuetral with Aurvandil. you could just go around
Seriously?
Umm.. several reasons:
1) The Véinsørmoot regards the Duchy of Paisly as rightfully D'Haran and therefore Little Italy there is an enemy (the fact that it was put there by Aurvandil only compounds the issue).
2) It is clearly nothing more than an attempt to slow down the Coalition's campaign whose secession came only to try to cause pause or disruption to the campaign.
3) It is an insulting offensive colonization of Véinsørmoot territory by Aurvandil; trying to implant their culture directly into the Maroccidens Proper.
4) It is made up of a bunch of Aurvandil nobility.
