A character's demesne (pronounced /dɪ'meɪn/, almost but not quite like "domain") will usually provide the majority of their income, as well as a decent amount of levies. It is within one's demesne that most construction occurs, including construction of new settlements in empty slots.
Each ruler has a demesne limit, and exceeding it causes a penalty to taxes and levies. This limit is what forces kings to distribute power to vassals rather than directly controlling their entire realm. A ruler's demesne limit is based on tier, personal and spouse stewardship, succession type, and centralization law.
If a character goes above their demesne limit:
- Demesne income will be reduced, increasing in proportion to how far above the limit he is.
- Negative demesne-related events become more likely.
- After 2 months:
- He'll receive a -10 opinion penalty for every settlement over the limit with their vassals
- Demesne levies will be reduced, except in the capital (-20% per settlement over limit, up to -90% with the 5th)
The demesne limit (as of patch 2.2) is:
Demesne limit = rounddown((Rank Base Demesne + Stewardship Bonus) * Gavelkind Bonus) + Law Bonuses
Each rank has a base demesne value:
1 a Great Duke is a Duke with 2 or more duchy titles.
On average Stewardship Bonus is 1 (8 stewardship), but in practice may range from 0 to 4. Roughly every 7 point in Stewardship (personal + half of spouse), will increase demesne limit by 1. Here is Google spreadsheet of stewardship levels, which can help you determine the necessary level stewardship to increase your demesne limit.
The formula is:
Stewardship Bonus = 0.15 * (Personal Stewardship + rounddown(0.5 * Spouse Stewardship))
Note: In case of polygamy, only the primary spouse's stewardship is used.
Tribal rulers get a +2 bonus to their demesne, at a cost of -10 to their vassal limit.
Centralization Bonus depends on the Centralization law, available to dukes and above:
|Level||Decentralized||Low Centralization||Medium Centralization||High Centralization||Centralized|
Patricians have different base demesne sizes than feudal lords. The base is 2 for a patrician and 3 for a doge, no matter what rank title they hold. (Was this changed with the removal of Legalism boosts in 2.2? - yes)
The in-game tooltip breakdown may be confusing, as values are rounded as integers for display, but formula uses float values behind.
Here's an example illustrating the tooltip discrepancy for a king with 12 stewardship married to a wife with 9 stewardship under gavelkind succession:
- Rank Base Demesne: 3*1 = 3, displayed as +3
- Stewardship Bonus: 0.15 * (12 + 0.5*9) = 2.4, displayed as +2
- Gavelkind: 30% * 5.4 = 1.6, displayed as +1
- Total: 3 + 2.4 + 1.6 = 7, displayed as +7 and not +6
Wrong settlement type
Characters get a 75% penalty to income and levies in demesne settlements that do not match their government type. These settlements should generally be given to a vassal of the correct type or to a courtier (who will automatically take on the correct type).
- Tribal rulers can only hold tribes without penalty
- Nobles can hold castles and tribes
- Patricians can hold cities and castles
- Muslim nobles can hold mosques, and gain extra piety if they do. Muslim patricians can no longer hold mosques without penalty.
- Nomads cannot hold any settlement without penalty except their nomadic capital.