To mitigate the effects, either grant extra titles to vassals or increase your domain limit. You can do this by increasing your stewardship, discovering technologies, buying perks, or changing your religion.
Exceeding Your Domain Limit – Debuffs
If you hold too many counties personally, then you will exceed your domain limit. You can find your domain limit in the upper right corner of the screen. For each county above your domain limit, a debuff is applied. The debuff scales as follows: This debuff is applied to all counties individually. The excess counties will still be active over the limit, but all of your counties will be debuffed, including those that were under the domain limit before. You should avoid reaching a -100% penalty. This used to be impossible since this debuff was capped at -90%, but a patch removed this limit. Note: Each county that you gain over the domain limit will be inactive for one year. It will not produce anything until one year has passed.
Grace Period
When you take extra counties over your domain limit, there is an initial grace period. This lasts for one year. During this grace period, you won’t experience the debuffs of your new counties over the limit. However, the new counties will also be inactive, as mentioned earlier. This means that you’ll have the same income and levies as before you took the excess counties until the grace period is over.
How To Increase Domain Limit
The fastest way to increase your domain limit is to increase your stewardship. Technologies, perks, and religions can also increase your domain limit.
#1 Increasing Stewardship
For every 5 points in Stewardship, you gain +1 domain limit. Councilors and spouses add to your personal attribute scores, so attracting highly skilled courtiers can also boost your own Stewardship. Your spouse can focus on Stewardship in the council with the option “Manage Domain,” which is especially effective if they already have a high Stewardship score. You can also focus on Stewardship yourself in the Lifestyle menu for a quick boost.
#2 Technologies
There is one technology in every era that grants +1 domain limit. These are, in chronological order:
Ledger (Tribal) Bailiffs (Early Medieval) Guilds (High Medieval) Court Officials (Late Medieval)
#3 Perks
The Stewardship perk Divided Attention gives +2 to domain limit, one of the largest permanent boosts in the game.
#4 Religions
The Pacifism and Dharmic Pacifism tenets both give +1 domain limit to all members of the religion.
Related Penalties And Debuffs
There are a few lesser-known penalties related to having too many titles or counties. The penalties that apply to you depend on your rank.
Too Many Duchies
If you’re a King or Emperor, you can have too many duchy titles, and this will affect your vassals’ opinions. Holding more than two duchy titles will reduce vassal opinion by -15 for each extra title. This can quickly add up into a large opinion debuff. Dukes do not get a penalty for having too many duchies, and Counts don’t own any at all.
Overextension
This penalty applies to Dukes and Counts only. If you have more than 30 counties in your realm in total, you will lose -5% income per extra county. Note: this includes vassals – it doesn’t matter who owns the counties, just watch out for your realm size! You can solve this problem by creating a Kingdom or Empire title, increasing your rank.
