Uther Period: What does Cadwy want?

[Uqbarian]

In the Book of Uther and the Book of the Warlord, King Cadwy is a weird old magician-king who seems pretty content to stay in his kingdom. There are also a couple of plot hooks between him and Salisbury, with the conquered hundreds and the unresolved forest rights. I'm thinking of running with those in my game, e.g. giving a PK a chance to play diplomat in sorting out rights and boundaries in the Forest of Gloom/Glamour, but what I'm stumbling on is what Roderick can offer Cadwy.

Obviously Roderick could give some of the conquered land back. But it also seems obvious to me that a warlord in Roderick's position is not going to give any of that land back unless he gets something even more valuable in return. Cadwy is at a level of power and influence comparable to Roderick's within Logres and even higher within his own domain. And I haven't yet come up with ideas for Logres-level politics where Roderick could offer something useful to Cadwy. (The closest I've got so far is to pressure Uther to negotiate the terms on Summerland's mineral rights, but I don't see it likely that Uther would give up much either.) Does anyone have suggestions?

(If this plot is still running when the Anarchy hits my game, then I can more easily think of things to negotiate over, as Cadwy is in a stronger position but can reasonably also be looking for allies, even though that goes against the line of the supplemements.)