Hypothetically, if Ysilla Royce was betrothed to Harry the Heir, how much would that be taken as a threat/insult to Robin Arryn? Especially during the period in which the Starks are at war and Lysa is holding back the Valelords, but also maybe even before Jon Arryn dies?

goodqueenaly:

Lysa, I think, would have certainly seen a betrothal between Harry Hardyng and Ysilla Royce as a move against her. For one, Lysa was already fearful of Yohn Royce during her Vale regency:

All the sternness melted off her aunt’s round pink face, and for a moment Sansa thought Lysa Arryn was about to cry. “Sweet Petyr, I’ve missed you so, you don’t know, you can’t know. Yohn Royce has been stirring up all sorts of trouble, demanding that I call my banners and go to war.[”]

What’s more, I would believe Lysa already knew about Harry Hardyng’s closeness in the Arryn succession. Little Robert Arryn states in no uncertain terms in Sansa’s first TWOW chapter that Harry is “just waiting for me to die so he can take the Eyrie”, and he had to have learned that from somewhere; a paranoid, overprotective mother dreadfully fearful of anything taking little Robert away from her seems a likely source. So if Lysa saw that Yohn Royce, so powerful and demanding, betrothed his own daughter to the boy who came after Robert in the Arryn line, I have to think she’d see it as an insult to her. Royce would be effectively saying at that point (certainly in Lysa’s mind) that he believed Robert Arryn would die childless, leaving the way open for Harry, and eventually his Royce-blooded son, to inherit the Vale.

Jon Arryn … well, I doubt he would have missed the subtle political implications of such a betrothal. After all, it would be rather surprising if, in the ordinary course, a daughter of the Lord of Runestone was betrothed to a mere landed knight bannerman of another Vale vassal House; the only reason Bronze Yohn would seek such an otherwise disadvantageous betrothal (unless some scandal had attached itself to Ysilla) would be because of young Harry’s high place in the Arryn line. Still, Royce’s conduct would be within the bounds of ordinary feudal politicking; Jon Arryn might have wondered why his greatest vassal seemed to be hedging his bets with House Arryn – publicly swearing fealty to him and his son while essentially investing in an alternate succession to the Eyrie – but would not have grounds to challenge it.

However, I think that if Yohn Royce had been interested in such a move, he would have been a bit more gradual and subtle about it than an immediate betrothal. I’d guess Bronze Yohn would try to secure Harry as his ward (though he’d have to have a pull with Anya Waynwood for that; Harry’s low on the Vale table of ranks, which would ordinarily make the offer of a fostering at Runestone automatically accepted, but Anya is no fool and would not surrender control of her dynastic prize easily), then imbue him with Royce ideology, then provide the way for getting him a knighthood as he did IOTL, and then marry him to Ysilla. All of those are natural steps for a lord to take, gradually swallowing Harry into House Royce.

Just thought of this, so sorry for not mentioning it earlier @goodqueenaly:

One reason why Jon Arryn would be less fussed about it is that he’s already had a long time to get alongside the idea of alternate successions before: first it was going to be his nephew Elbert, then it was going to be his cousin/nephew-in-law Denys. 

And Sweetrobin is not healthy, so one has to think practically.