Daeron the Good and the Stormlords

[OmnomnomPomelo]

So in the past the Targaryen married mostly each other to keep their blood "pure". But then Baelor the Blessed made a Peace Treaty with Dorne, thus Daeron the Good married Miriah Martell, and Daenerys with Maron Martell.

Then Daeron's 2 older sons married Stormlanders, Baelor married a Dondarrion girl and Aerys a Penrose one. The other 2= Rhaegel+Arryn girl and Maekar+Dayne girl. So the Stormlords got this "honor". I'm sure there were living Targaryen (and Velaryon) women with whom they could keep their blood pure, so it had to be some kind of political marriages. So the royal family felt that the ground is not stable under them? Were there some kinds of dissidence between the Targaryens and Stormlords? Also we that the Baratheon's predecessor (Orys) arrived to Westeros with the Targaryens, but the latters didn't marry them, so this could generate some problems something like when Egg's son didn't marry Lyonel's daughter.

Is there anything about this in TWOIAF? I don't remember.

[Vikingkingq]

Well, it would partially explain how the Stormlands flipped from hating Dorne under Aegon IV to supporting the Reds in the Blackfyre Rebellions.

[Lord Varys]

Daeron's son had not close female kin in their own age. But Aelinor Penrose was a cousin of Aerys I, suggesting that Baelor, and possibly Maekar as well, were married to descendants of either Baela or Rhaena Targaryen (through various generations, of course). Alyn Velaryon may not have had any (great-)granddaughters in the right age to marry to Daeron's sons.