Some months ago I was thinking about how inherentence would play out of my family would be medieval nobles. Since my area had always been traditionally male primogeniture where the firstborn son gets the whole estate with no splitting of property, it turns out that I would be the heir of all my eight great-grandparents.
Simplifying things, we have three different estates of three of my great-grandparents in different parts of Holstein. (The fourth was ceded to the King of Poland.) My father inherits #1, and my mother #2 and #3. And I inherit all three.
The next in succession after me would be my father's brother's son. Since my father's brother was the third son with nothing to inherit, he married into a family in Saxony. His son, my cousin, was born and lived his whole life in Saxony.
Here it get's interesting. While his claim to estate #1 is perfectly clear cut and unambiguous, my mother's sister's son might be quite upset that he's to see his grandfather's estate on which he grew up given to some noble from Saxony he has no direct relationship to and who's never even been to the place. I guess I would have made him the steward of estate #2, so he's already in control of it and knows all the staff and tenants his whole life. He also is friends with many other nobles in Holstein, including his younger half-brother who is the owner of a really big estate himself. (He gets an honest to good farm instead of a single family house.
)
Now if my cousin from Saxony shows up in Holstein to claim his three estates, and my maternal cousin who has manged them says he can have #1, but won't get #2 and #3, what's going to happen?
The Saxon cousin might have a claim according to the letter of the law, but the Holsteiner cousin has possession of the land and contacts to other local nobles, including his own brother.
No clue about the maternal side of my Saxon cousin. If his mother is from a nobody family with no power, he's going to have to suck it up and be greatful that he at leasts gets the land from his own grandfather. But if his mother is from a big and powerful Saxon family ready to march north, then things are going to get really interesting.
If I'll ever find myself in need for a dynastic struggle, I'll be using those inheritence rules and make it about the old lord's paternal and maternal cousins.