Since the patch that came with the Art of War expansion, it is possible to start wars to reconquest core provinces from enemies that belong to your vassal.
However, when I finally win and capture those provinces, I have no option to return those provinces to my vassal. Instead I can only annex them myself. I can sell them to my vassal afterwards, but I get unnecessary AE this way for provinces I never wanted for myself in the first place.
Is there a way to return those core provinces directly to my vassal in peace negotiations? If yes, under which conditions will this option show up?
Best Answer
It seems that your vassal actually needs to control a province so that you can demand its return to him in the peace treaty.
When you are in control of the province, it's possible to pass the control on to your vassal in the province dialogue. Note that this only works if you have the Art of War DLC.