Τζον Σνοου και Μραν Σταρκ

[Seviren]

So Spake Martin july 27  2008

[Questions concerning Targaryen polygamy.]
Maegor the Cruel has multiple wives, from lines outside his own, so there was and is precedent. However, the extent to which the Targaryen kings could defy convention, the Faith, and the opinions of the other lords decreased markedly after they no longer had dragons. If you have a dragon, you can have as many wives as you want, and people are less likely to object.

http://www.westeros.org/Citadel/SSM/Entry/2997