..... umm .... but.... we already did... do you remember the whole reason we went to Marienburg in the first place? and what we did in Marienburg?[X] Plan North and South
Actually, come to think of it, we ought to talk to Matriarch of the cult of Manann before talking to Magnus.
If Magnus does bring up that whole mess on his own, then Frederick would then have more than a sort of apology, he'd have a game plan.