yeah also in england and i'm scots 20% unrest and religious unrest
england still lives in bruges and groningen
100% cathlic
i did read in an other topic that generals with low piety grow religious unrest
occupy = controlling the people who live there and keep them alive, nut they will cause unrest(chivalrous)
sacking = robbing the place, you gain money (neutral)
Exterminate = kill all most of them so they wont caus unrest, but you kill tax payers

(dread)
so far upgrading churches to abbey make religous unrest slightly go away
edit: so far you alwsy have some unrest but you buildings make up for it