Well, Aurvandil and Madina are both growing greatly thanks to the dissolution of Caerwyn. The Saxons appear to be moving en masse to Aurvandil while another faction in Caerwyn heads for Madina. Aurvandil now has the knights to expand significantly, including northward should they so desire. But the Veinsormoot would crush them you say? Has the threat of destruction *ever* stopped the Saxons from doing stupid things before? 
Or, maybe they'll just try harder to kill Madina. I'm not sure about that though, seeing as Madina is also growing and can as a result easily hold Tower Fatmilak against cross channel assaults... If they don't screw up.
A lot of the Saxons have joined nearby realms to Aurvandiel (Barca, Terran), it could be regular post realm collapse dissolution or a clever plan to create sympathy for Aurvandiel in those realms.
As far as I know only one or two nobles from Caerwyn have joined Aurvandiel.
