If they're residing in Matilda's court then they count as her vassals rather than yours, so you don't get the option to give them titles directly.
Thanks, makes sense. I had three sons, and I think I chose to educate one myself (since the Polish King = mad martial skillz), is that a way around this? I suspect that I didn't check all of them carefully enough. Also, Matilda died at 34, which I assume, means that they moved to their own courts, and so were residents of Italy until they inherit Polish Dukedoms/Kingdom.
So I'm playing as the King of Poland, succession law is gravelkind and not surprisingly I'm getting the "title lost on succession" alert.
My 2nd and 3rd son will inherit several ducal and county titles. Will my heir be their liege on succession, or will they become independent?
Like Wezqu said. It seems to me that Gavelkind splits your holdings if you have multiple top-tier holdings. If you have one top-tier holding it's not
as bad, but you still end up like Phillipe Capet - nominally in charge, but holding nothing more than your largely empty title. You're stuck expanding constantly to keep personal holdings, and the jump from a single Dukedom to King will require one great, or long-lived ruler.
For primogeniture, it looks as though we're intended to either:
1) start as a low enough person that we can switch to primogeniture before we advance (is there such a thing anymore)(does this even work? if I choose primogeniture as Count, do I get the ducal/kingdom laws when I move up, or keep my County laws?); or
2) suffer serious losses (if we expand) every time there is a succession until, by several generations of moves up the Crown Authority ladder we're finally able to switch to primogeniture.
If #2, vassals will constantly be pushing back. They'll try to reduce Crown Authority upon every succession, against a ruler who is definitionally weaker. This seems as though it will take many generations. I get that "switch to primogeniture on Day 1" is the kind of no-brainer that game designers like to avoid. I also get that it produces very ahistorical Kingdoms by 1200 nevermind 1300 or 1400, but this seems like a recipe for frustration. As it appears to me now, it's entirely possible that you are theoretically permitted to have primogeniture, but you'll rarely actually get to it. OTOH elective doesn't look that bad (see ParadoxianLP's Denmark game).
If this is all true, I wonder if I'd prefer "Primogeniture not unlocked until 'Kingdom Theory 3'" or some set date rather than always available but never within reach. I guess I'll have to play it and see.