How to start a war? Sweden has been at peace forever....

[Vampiresbane]

So I joined Sweden to have access to Scottish mercs.  Go Scotland!

But alas, Sweden has been at peace FOREVER and now I can't really make war on anyone.

Is there any way to foster a war or get your King to get his royal bottom in gear?

 

[Nhatorama]

You could go "One Man Army" on anyone you wish.

Spoiler

I'm pretty sure you're eyeing Polish or Muscovite fiefs, so attack their caravans or traveling villagers to bring your relation with them in the negative.
Wage your war of attrition (you probably won't be able to capture a fief with just one siege) by sieging a fief repeatedly and make sure to retreat when you're the last man of your army standing.
Eventually when the nation you've been waging war feels like Sweden has expanded too much, it will declare war on Sweden.