Celtic culture (Breton, Irish, Scottish, or Welsh).In order to change the succession law to Tanistry a ruler needs to meet the following conditions: The oldest child of the ruler has a -40 opinion penalty towards their parent (if not the Tanist), all other dynasty members have a +10 opinion boost, and all vassals have a +5 opinion boost. Vassals will tend to favour older members from other branches of the family, especially claimants. With Tanistry succession, the ruler and all vassals at one and two ranks below can nominate an heir - the Tanist - from among the members of the ruler's dynasty. In order to change the succession law to Feudal Elective a ruler needs to meet the following conditions: If the ruler holds too many elector titles the vassals will not approve. The oldest child of the ruler has a -30 opinion penalty towards their parent (if not the heir), all other dynasty members have a -5 opinion penalty, and all vassals have a +20 opinion boost. Dukes are valid electors in both kingdoms and empires. dukes if the ruler is a king) can nominate a successor from among themselves and legitimate children and siblings of the ruler. The ruler and each lower rank vassal (e.g. With Feudal Elective succession, all titles of the ruler pass to a single elected successor. The Crown Authority must be high or absolute.In order to change the succession law to Primogeniture a ruler needs to meet the following conditions: All dynasty members except the successor have a -5 opinion penalty. In the absence of children, inheritance passes to collateral relatives in order of seniority of their lines of descent.

With Primogeniture succession, all titles of the ruler are inherited by the oldest child. The Crown Authority must be medium, high, or absolute.In order to change the succession law to Seniority a ruler needs to meet the following conditions: The oldest child of the ruler has a -30 opinion penalty towards their parent, all other dynasty members have a +10 opinion boost, and all vassals have a -10 opinion penalty. With Seniority succession, all titles of the ruler are inherited by the oldest member of the dynasty. No vassal of count rank or higher has a negative opinion of the ruler.Has not previously changed the succession law.In order to change the succession law to Gavelkind a ruler needs to meet the following conditions: The oldest child of the ruler has a -10 opinion penalty towards their parent, all other children set to inherit have a +10 opinion boost, all other dynasty members have a +10 opinion boost, and all vassals have a +5 opinion boost. There is no prestige penalty for having unlanded sons, and Gavelkind confers a 30% increase in max. If the ruler has no children that can inherit, the law reverts to Primogeniture. With Gavelkind succession, the titles of the ruler are divided among his/her children.

Ck2 create new vassal