How to declare war? (Crusader Kings 3)
The question, as they say, is to fill)need a claim to an area that can be created with the help of the Chancellor (a character that can be sent to the area to fabricate a claim or evidence - I do not remember exactly). In addition, you can capture through the war territories that are part of the title, which belongs to either the player or the vassal player (in this case, the player will not receive direct control of the territory).
SHTIRLITS
The chaplain (whose scholar in the case of Christians is a bishop) must create a case of belli in the area (county). When you create - you can declare war, with the condition of victory - getting a county.
Also - if the enemy is an innovator - you don't even need a chaplain with a casus-belli. There is an option "holy war for the county/duchy and even the kingdom" (ahtung - need piety!)
Wars can also begin if you have a possible owner in the county at the court. For example - the territory is owned by a person A from one family, the second person (B) does not like it and he escapes to another kingdom (to you). Then you have the right to start a war for the possession of this territory for the benefit of yourself (person-B) will become the new owner and your vassal in case of victory.
And one more thing. De jure titles. For example, you have restored some kingdom. For example - I restored Belarus (the name of the kingdom of White Russia), but some of the areas - in the possession of other monarchs. I have the right to declare war on them in order to introduce de jure titles (along with the regions) into my power.
