法律
法律（Laws）とは領国（realm）の発展に極めて重大な影響をもたらす王法のことです。
権限
封建制（Fedal）と氏族制（Clan）政府は王権法（Crown Authority Law）を利用できます。これは必要な革新性を研究すると権限を引き上げることができ、20年ごとに変更可能です。レベル2の王権は部族時代（Tribal era）に属する
民会の革新性が必要で、レベル3とレベル4は中世初期時代（Early Medieval era）に属する
君主大権の革新性が必要です
部族制政府は部族権限法（Tribal Authority Law）を利用することができ、権限を増加させるために革新性を必要としません。そして法律は10年ごとに変更可能です。権限法を変更するコストは支配者の領国（Realm）サイズに比例します。また影響は少ないですが支配者の
学識能力にも比例します。
| 権限 | レベル１の効果 | レベル２の効果 | レベル３の効果 | レベル４の効果 |
|---|---|---|---|---|
| 王権 |
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| 部族権限 |
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称号の剥奪が可能
すべての分割相続法が利用可能になる
氏族制政府の封臣は最低2％の収入を供出する
氏族制政府の封臣は最低5％の徴募兵を供出する
称号の剥奪を拒否（Refusing Title Revocation）は犯罪（Crime）となる
主君のディシジョンを通して封建制を受け入れる（Adopt Feudal Ways）が有効になる継承法
There are three types of law affecting succession to a title: gender, realm and title. Changing gender or succession laws costs 500 
prestige and requires all powerful vassals to either have a positive 
opinion of the liege, be imprisoned or be terrified.
法律が関係する継承（succession）には性別（gender）、領国（realm）、称号（title）の3種類があります。性別法や相続法を変えるには500の 威信が必要です。またすべての有力な封臣（powerful vassals）が祝に対して肯定的な 評価を持つか、投獄されているか、畏怖を感じている必要があります。
性別法
The gender law determines which gender can inherit titles and claims and who can have more than one partner if its faith doctrines allow. The 
Visigothic Codes innovation gives access to Equal succession regardless of faith.
| Law | Inheritance | Concubinage and polygamy | Required views on gender doctrine |
|---|---|---|---|
| Male Only | Men only | Men only |  Male Dominated
|
| Male preference | Men take precedence | Men only | Male Dominated Equal
|
| Equal | Both genders | Both genders | Equal
|
| Female preference | Women take precedence | Women only | Equal Female Dominated
|
| Female Only | Women only | Women only | Female Dominated
|
Realm succession
The realm succession law determines which and how many heirs will inherit the character's titles upon death. All children will gain claims on titles they did not inherit regardless of the realm succession law.
| Heir number | Law | Required innovation | Opinion | Effect |
|---|---|---|---|---|
| Multiple Heirs | Confederate Partition |  Gavelkind
|
+5 Direct Vassal +5 House +10 Eligible Child |
Upon succession, all titles held by the late ruler will be divided amongst their eligible children, with the player heir always being given the primary title, realm capital and any direct de jure titles associated with it. Younger children will be given titles starting with those of the same rank as the primary title, if none are available they will be given lower-ranking titles. Children can not be preemptively granted titles they do not stand to inherit. Younger children will have titles created for them, if enough land is held. |
| Partition |  Hereditary Rule
|
+5 Direct Vassal +5 Eligible Child +10 Player Heir |
Upon succession, all titles held by the late ruler will be divided amongst their eligible children, with the player heir always being given the primary title, realm capital and any direct de jure titles associated with it. Younger children will be given titles starting with those of the same rank as the primary title, if none are available they will be given lower-ranking titles. Children can not be preemptively granted titles they do not stand to inherit. | |
| High Partition |  Heraldry OR Visigothic Codes
|
+5 Direct Vassal +15 Player Heir |
Upon succession, all titles held by the late ruler will be divided amongst their eligible children, with the player heir always being given the primary title, realm capital and any direct de jure titles associated with it. Younger children will be given titles starting with those of the same rank as the primary title, if none are available they will be given lower-ranking titles. Children can not be preemptively granted titles they do not stand to inherit. The player heir will always inherit at least half of the late ruler's titles. | |
| Single Heir | Primogeniture | Primogeniture
|
+20 Player Heir -5 Eligible Child |
Upon succession, all of the late ruler's titles will be given to the player heir, which is their oldest eligible child. Younger children will receive nothing. |
| Ultimogeniture | Primogeniture
|
+20 Player Heir -5 Eligible Child |
Upon succession, all of the late ruler's titles will be given to the player heir, which is their youngest eligible child. Older children will receive nothing. | |
| House Seniority | Heraldry OR Table of Princes
|
+5 House -5 Direct Vassal -15 Eligible Child |
Upon succession, all of the late ruler's titles will be given to the oldest eligible member of their house. Your children will not be given anything, unless one of them happens to be the oldest house member. |
Title Succession
Feudal Rulers can apply a Title Succession Law on Duchy, Kingdom or Empire titles at the cost of 1500 Prestige. Note that this will only affect the succession law for the title in question; other titles the character holds will be distributed normally. (This can lead to unexpected results.)
| Law | Direct Vassal Opinion | Effect | Requirements |
|---|---|---|---|
| Feudal Elective | +10 | The Ruler and all direct De Jure Vassals of one or two Ranks below the Title can nominate an Heir from amongst themselves and the Close Family of the Ruler. | Not Anglo-Saxon culture Not North Germanic culture group |
| Saxon Elective | +5 | The Ruler and all direct De Jure Vassals of one or two Ranks below the Title can nominate an Heir from the most Powerful Vassals amongst them, the Ruler's Legitimate children, and any other valid Claimant. | Anglo-Saxon culture Title rank is kingdom or empire |
| Scandinavian Elective | +5 | The Ruler and all De Jure Vassals (except Barons) can nominate an Heir amongst the Ruler's Extended Family and any available Claimants. Voting Power in this Succession Law is influenced by the Elector's total Domain Development and Capital Popular Opinion. Known criminals are not eligible Heirs, but their descendants are. Grandchildren of non-criminal, living children are not eligible Heirs. | North Germanic culture group |
| Tanistry Elective | +5 | The Ruler and Vassals of one or two Ranks below the Title can nominate an Heir - the Tanist - from among the members of the Ruler's Dynasty. Vassals will tend to favor older, distant relatives over Close Family. | Brythonic or Goidelic culture group Title rank is kingdom or empire |
| Princely Elective | +10 | The Emperor and the seven Prince-Electors can nominate an Heir from amongst themselves, any Legitimate children and siblings of the ruler, as well as any other major De Jure Vassal of the Empire. If an historical elector Title is held by infidels or does not exist, another De Jure Vassal will take its place. This Succession Law places a significant importance on Faith and Piety. The Electoral Titles for this realm are the Counties of Cologne, Mainz and Trier, and the Duchies Bohemia, East Franconia, Ostfalen and Ostmark. Removing this Law costs 10000 Prestige. Having this Law active increases the vassal limit by 20. |
Holy Roman Empire title |
Strategies
- Monitor which holdings will be lost upon succession: Click the "Succession" tab under the "Realm" window.
- Get out of Confederate Partition as soon as possible: It is the only succession law which creates new titles upon succession, thus almost guaranteeing a split in the player's realm unless the player restricts the realm to the De Jure Counties of their primary duchy or kingdom. If expanding, they should aim to occupy at most 50% of other duchies/ kingdoms to avoid having enough land to cause a split.
- Tribal realms are locked to Confederate Partition; they must reform to either Clan or Feudal government before being able to select other succession types.
- If you have a partition succession and multiple heirs, you may want to remove all heirs except one, if possible, so that your primary heir inherits all titles. This is difficult to do, but there are ways. (Sons with low prowess can be forced to serve as knights, and may die in combat. If you are the dynasty head, you can disinherit all heirs but one. If you have the sadistic personality trait, you can use murder schemes against your children. Etc.)
- If an event allows you to choose an "elective" title succession law, be aware that this only applies to the title in question. For instance, if you play as the King of Scotland (Goidelic culture group) and you have partition succession, switching Scotland to "Tanistry Elective" will not affect how your duchies and counties are distributed. When you die, if your primary heir is not your tanist, you may find yourself playing a new king with very few holdings and a great deal of internal "border gore".
- If you have another kingdom in addition to Scotland, then Scotland will be completely removed from partition. All your titles under de jure Scotland will be inherited by the tanist, and your children will inherit the second kingdom and other external titles. This will split your former realm but you will not lose all your domain. On the other hand, if this second kingdom is also under tanistry, it will also be removed from partition and your children will only divide your titles outside of both kingdoms. This will not split your realm, but the electors in both kingdoms have to elect the same person.
- If you only have one kingdom with tanistry and partition, you can save your domain by adding tanistry law to your duchies. This is expensive (1500 prestige) but such a duchy will be removed from partition and its de jure counts (which is usually only you) will vote for the successor of the duchy title. You should appoint the same person who is going to inherit the kingdom.
Additional Info
"Succession Laws EXPLAINED", forum thread: https://forum.paradoxplaza.com/forum/threads/succession-laws-explained.1419049/