I often wondered how is it that certain regents get to have law holdings in other regent's domains. Yes, there's the explanation that this made game more interesting and allowed powerful regents like Avan or Boeruine the reason to meddle in their neighbors affairs and control vassals, but one rather simple concept would greatly enhance the game experience, even though it will probably be applied very rarely, and that's dowry.
When a woman of high birth was married to a knight, count or even king, it was expected that she bring with her a dowry in accordance with her rank and status, be that money, goods or estate. Usually it was the husband who controlled the dowry, but legally it wouldn't be considered legal property of the dynasty until a male son inherited it.
In Birthright it is quite concievable that instead if, for example, Avan was marrying the daughter of the Archduke of Alamie, instead of getting 30-40GB, the archduke would give "his daughter" and in fact his son-in-law, and their heirs, 2-3 levels of law. I can't dig up the actual nunbers but an estate was usually worth 10 times or more than its annual income.
This is, of course, just a roleplaying suggestion, but a dowry should be used in those few cases when our regents get to marry. How much for particular counts, barons, or dukes, I'm not exactly sure.
It was however, inconcievable, that a medieval noblewoman would marry without one.
