why don't I have a de jure CB to vassalize dukes?

[mib]

King of France here, took over after offing the supremely incompetent Capets.

Problem is, the Capet guys basically allowed the duke of Aquitaine to declare independence and walk away with basically half the kingdom.

Now I want to DOW Aquitaine to bring them back to the fold, but cannot. I can press a bunch of title county titles, but nothing duchal level or above. He has 3 duke titles, all of which belong to my kingdom de jure. What am I missing?

 

[DreadLindwyrm]

Nothing. Kingdoms do not get de jure claims on dukes. This may be because of the sheer volume of claims it would generate.

If you press the county claims on them you may be able to get enough to usurp/claim the duchies, and then you can claim the other counties.
Alternatively, if your advisors are good you may be able to generate a claim directly on the duchy, and then war for it.

 

[Dark3lf]

Find a claimant of that duchy, invite it to your court, and you can declare war for the duchy owner. As long as the Duchy is in your kingdom de jure area, you will get the claimant as your vassal.