Overall explanation of inheritance rules?

[unmerged(246856)]

I'd love a one-page (or more) breakdown of how all inheritance works in the game. Such as, will me marrying a female cousin consort of mine to a count somehow lead to me gaining a province? Does marrying my son to a duchess give his son claim to a province, and will that province come under me directly, or be a vassal, or ?

This is by far the most confusing aspect of the game, and I really don't know what to even look for when marrying people away. Especially in my new game, where I started with about 15 children and they all want to get married off.

 

[DreadLindwyrm]

The simple version of the inheritance laws is as follows:

Agnatic = only men are allowed to inherit.
Agnatic-cognatic = men inherit ahead of women
Absolute cognatic = men and women inherit equally, based on birth order

Elective = you and your vassals (one level below you) vote on the next ruler.
Primogeniture = oldest eligible child inherits
Gavelkind = your titles are divided as evenly as possible between your children
Seniority = the oldest surviving member of your dynasty inherits.


This is slightly complicated by the fact you can have different inheritance laws for different titles.


In general, the top two contenders for a title that don't inherit it will get a claim and a special CB to try to claim that title.

If your son is your heir, and also the heir of your wife, then on each of your deaths he will inherit your titles.

 

[Makesin]

Marrying your son to a countess/duchess/queen doesn't bring you anyting in the short term. Your son becomes the consort and leaves your court (if he doesn't have his own title already) which also means that all their children will be courtiers our your daughter-in-law (unless, again, your son doesn't have a title beforehand). If your son gets a title after he has children, they stay with their mother, so you won't be able to do anything about their education. IIRC, you should be able to invite them to your court after they mature (at least if you are already playing as the son).
Of course, your grandchildren are both your son's and daughter-in-law's heirs, so once you will play as them, you will unite both lands.