Can't declare war with a diplomat, only with assassins and troops.

I think Moors or Iberia might be a better target in a few diets time. At the moment, Mongols might be the better target. I would prefer that we only declare on them if they attack an ally, but not for no reason. I guess we could invoke Heinrichan rules to attack Mongols if they trespass, but which noble who governs a province would be bold enough to do that?