Gavelkind is a ponzi scheme like the Assyrian Empire. Always conquer new Land so can hold your crown land. If you dont conquer you become always much weaker.
In reality the Kings, especially the Kings of France, tried to expand their crownland since 1066. I dont think Primo should be 1200.
In my opinion the player should decide what he wants to play. Atleast mods can fix this.
We can even look at much older dates. In the kingdom of Israel and Jerusalem there was succession by right of birth (1000 years before Christ).
David inherited the 2 kingdoms to Solomon and this to his son ... I could continue, but the idea was already understood.
Solomon was not the firstborn, but he was the best and wisest of all his children, so David discarded all his other children and passed everything on to one, naming him his "Firstborn" and inheritor.
The good thing is that in CK3 we can also do that and in tribal too.
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