Crusader Kings III – Building bonus guide

Holding

They are the individual cities, castles, or churches you see on the map. Holding Boni (This Holding) are resources and levys, very simple. If you control the Holding, it counts towards your Domain cap; you will get everything they provide. Otherwise, you will only get a cut according to their type:
City: 20% Gold / 10% Levys
Leased Temple: according to standing with realm priest. 0 / 0 at 0 opinion up to 50% / 100% at 50
your religion needs to have Theocratic Clerical Tradition to lease Temple
Castle / Temple: 10% Gold / 25% Levys as Feudal
according to your standing with them 0 / 0 at -100 up to 25% / 60,5% at 100 as clan

County

A County is a collection of Holdings. Usually, you will have the main Holding, and a Vassal will hold all the other ones. Like I said above, that means that you will only get a cut of what they provide.
County Boni (This County) will always be applied to every Holding in the County, whether you control it or not.

Duchy

From this point on, it should be quite clear what they are, and I will stop explaining.
Duchy boni comes from special Duchy buildings. For them to work the Duchy title and the Duchy capital, so the place where the building is located has to have the same owner. Otherwise, they will be inactive.
Their boni (All your Holdings in the Duchy) will only be applied to the food chain downwards. So if you have it, all your Vassals will get the boni too, but if a vassal holds it and you have a County in the Duchy, you will get nothing.

Realm

The Realm boni (This Realm) is probably the most misleading thing here, as they are not applied to your Realm but you instead.
Lots of buildings will have Realm boni, but you have to control them to get them as in: counting towards your Domain limit. Even Holdings in your County will not provide their Realm boni to you.
So Barracks in a Holding in your County held by a Vassal will not give your heavy infantry better stats. The only way around this is by having a religion with Theocratic Clerical Tradition because then you are still the owner of the Holding, but because it is leased out to the church, you will get only a cut of its resources but still all of the Realm boni the Holding provides.*

* Currently, there is a bug with getting the boni; while to tool tip from hovering over the temple says you´ll get the boni, you don´t actually get them.

Conclusion

Conclusion

Especially for Feudal rulers with Theocratic faith, curches may be the best Holding to build in your County if you have more than 3 slots. While a city might yield higher base gold and a castle higher base levys, a church will give you a higher gold cut, given that they contain the same buildings.
And of course: Build gold in cities,
as Feudal: levy in castles you don´t control directly,
as Tribal or Clan: castles are a bit more flexible but still favor levys.

I hope this will be of help to you.

This is all about Crusader Kings III – Building bonus guide; I hope you enjoy reading the Guide! If you feel like we should add more information or we forget/mistake, please let us know via commenting below, and thanks! See you soon!