I'd first check if the mod structure itself works.
For that you could use a character history file and change just a single attribute, trait or so, something simple to verify in-game if the mod structure works as such, before you lose your mind trying to find the error where it isn't..

Just going by the assumption you did everything correct based on what you said you did, it should work as far as i recall modding de-jure structures.

Not knowing what your mod actualy looks like...
Maybe copy the whole landed_titles file, if you didn't do that and modify that. Be sure to cut Cornwall duchy and county from Wales and not only copy it.

That should already prevent some errors one might make in the attempt or in hindsight then provide better ideas where/what the issue might be.

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Apart from that, by my experience modding questions are best asked in

the PDX forum
https://forum.paradoxplaza.com/forum/threads/modding-quick-questions.589686/

or on Discord (for example at Crusader Kings - ck2-mods) https://discord.com/channels/616881873506795550/631394732664422401
(there is also a specialised CK2 modding 'server'on Discord, but i ain't sure if they mind spreading the server link or not)

Originally posted by Varainger:

I'd first check if the mod structure itself works.
For that you could use a character history file and change just a single attribute, trait or so, something simple to verify in-game if the mod structure works as such, before you lose your mind trying to find the error where it isn't..

Just going by the assumption you did everything correct based on what you said you did, it should work as far as i recall modding de-jure structures.

Not knowing what your mod actualy looks like...
Maybe copy the whole landed_titles file, if you didn't do that and modify that. Be sure to cut Cornwall duchy and county from Wales and not only copy it.

That should already prevent some errors one might make in the attempt or in hindsight then provide better ideas where/what the issue might be.

-------
Apart from that, by my experience modding questions are best asked in

the PDX forum
https://forum.paradoxplaza.com/forum/threads/modding-quick-questions.589686/

or on Discord (for example at Crusader Kings - ck2-mods) https://discord.com/channels/616881873506795550/631394732664422401
(there is also a specialised CK2 modding 'server'on Discord, but i ain't sure if they mind spreading the server link or not)

I couldn't get it to work somehow When I modified the file from the game directly, it worked, but as a mod, it doesn't work

Originally posted by M82:

Originally posted by Varainger:

I'd first check if the mod structure itself works.
For that you could use a character history file and change just a single attribute, trait or so, something simple to verify in-game if the mod structure works as such, before you lose your mind trying to find the error where it isn't..
....

I couldn't get it to work somehow When I modified the file from the game directly, it worked, but as a mod, it doesn't work

I guess you mean you did get it to work when you modified the file inside the game folder directly, just not when you created a mod ,right ?

Then do what i suggested first, test if the mod as such works with another example.
I suppose not, but try it.Then report back.

When you create a standard mod, so NOT packed as a zip,but as an unpacked folder,
the modname.mod file has to look diffferent then when you get it from the Workshop.

Example :
name = "My mod"
path = "mod/mymod"

So not "archive"and no "*.zip" at the end of the modname in path.