actual use of marriage

[Graydon Hicks]

ive been thinking, how often do the lords paramount actually use their children in marriage alliance outside of their home provinces? i mean, i know cat and lysa, ladies of the north and vale, respectively, were originally from the riverlands, the lyanna was supposed to married robert, from the stormlands, but how often are marriages actually used like that? i read somewhere that the Northmen were not all that happy about their House paramount was taking spouses outside the north; of course that could just be the natural clannishness of the First Men blood families. but i got an impression that more often the children of a lord paramount, and lords in general, were married to other families within their native provinces, to improve the relationships between a lord and his bannermen. and you cant count robert marrying cersie or trying to betroth joffrey to sansa, or use rhaegar and elia. the royals arent really bound to a province.

[The Hoare]

It actualy make sense to marry someone from the same province as yours. If something happens, a local lord is more likely to help you than a lord from another region.

But it's not all that rare marriages between different provinces. Harmund II  Hoare took a Lannister as wife, Quellon Greyjoy married a Piper, and there is at least 3 Starks that married members of House Royce.

The Freys married people from half of the kingdoms too.

[Graydon Hicks]

so it might be a case of the Northerners just not liking bringing in any of the southern andals.

but i do pick as my best example for keeping the family in the province as the tyrells, olenna was a redwyne, mace married a hightower, and garlan has a florent bride, all reach houses. and when i look over the history book, there not that much mention of the spouses; plenty on individual nobles, and their heirs, but not much on their spouses. the only part that really goes into spouses is the chapter on the targaryen dynasty, and the wives of the targs.

[SeaWitch]

There's an element of social rank involved.

A real world issue like this arose during the reign of King John.  He had a habit of marrying off women with property as rewards or bribes for his followers, some of whom were either foreign or of lower birth. This 'disparagement' caused a lot of bad feeling and was a major grievance with the nobility.

Martin nails it quite well in most cases.  Everyone wants their children to marry across or up.  A family with extra daughters might marry one a rank down to secure the loyalty of a lesser house, but they'd expect the heir or someone very senior.  Marrying a daughter up requires a fortune behind it.  

"Titles do seem to breed titles" was not empty sarcasm, but a bitter truth.

Marrying too far abroad geographically might be problematic, unless it is to secure military or trade alliance.  The North is the size of the other six kingdoms combined, plenty of bannermen to keep sweet 'locally', and yes, a slight cultural bias.  

Historically, Tywin proposing Cersei as a royal match was not out of line, she did have rank and wealth.  Petyr Baelish being matched to a Tully daughter was an extreme mismatch - he might have stood a chance with a daughter of a more minor house, Lynderly or the like.  It would be interesting to find out who Hoster Tully had in mind for Edmure, matching his two daughters to the North and the Vale made a huge power block.  He was trying to push the Blackfish to a Reach family.  As you say, their tendency to make close alliance within their own province means a strong region, so marry into one, you get the lot.