Is making a vassals from my own country a good idea? How to use it in the best way?

[W1NTERMU7E]

Im playing Jerusalem rn and my country is getting bigger and bigger and I feel like I leave some parts of it not developed and untouched. Would making vasssal from certin areas a good idea to "auto" develope them?

 

[Nwaij]

1. Find a province on your land some extinct nation has a core on. Ideally one singular province, but have to work with what you have...
2. Release vassal from said province via diplomacy tab. Enforce religion as needed.
3. Declare war on neighbour who outrageously holds core provinces of your vassal using reconquest CB. Feed additional land to vassal as war score & AE allow.

Not knowing your specific situation, more specific suggestions can not be made.

 

[Richard-monagha]

If you can post a screenshot of your current game map we can give some suggestions. for releasable vassals to reconquer land for.

 

[agonistes]

Im playing Jerusalem rn and my country is getting bigger and bigger and I feel like I leave some parts of it not developed and untouched. Would making vasssal from certin areas a good idea to "auto" develope them?

That absolutely can work if you want more dev. I frequently vassalize Italians who go ham with devving.