Once you have a claimant in your court, you will gain a Casus Belli against the current holder of the title that is claimed. When selecting ‘Declare War’ in the diplomacy window, you will have a Casus Belli with a portrait next to it showing the claimant who you will be installing should you win.
If you are unsure if the Cornwall or Gloucester listed is the county or the duchy, mousing over the claim will give a detailed tooltip with all the relevant information on the casus belli.
In many cases the individual with the claim will not be interested in joining your realm after you have installed them. If you are pressing a claim to a title equal or greater than your own (duke installing a duke, king installing a king, duke installing a king, etc), there is no chance that the Claimant will stay part of your realm. While the bubble help tells us that they will join if you are of the same dynasty, or if you are the de jure liege of the land taken, these are not the only instances where land can be gained. It appears that the game automatically issues an offer of vassalization to the leader at the end of the war over the claim, and if the newly installed claimant would accept an offer of vassalization, then they do so and are immediately part of your realm without you having to ask. Modifiers to the vassalization check include: distant realm, is de jure liege, power, opinion, difference in rank, foreign culture, and likely more. As a powerful King, you can install a same-culture, different-dynasty count outside of your de jure lands and successfully add them to your realm, even though the individual will not meet any of the criteria set out in the bubble help. Getting just the right claimant can make all the difference.
While pressing claims is a good way to add territory to your realm, it is important to note that it will never directly add territory to your demesne, as it will always belong to the individual with the claim after the war.
Other Claimant Topics