You can get a truce with him the same way as any other faction. Defeat his army and make him withdraw to his castle. Withdraw your troops and send an emissary to offer peace/alliance. It works: present campaign I trounced his largely garbage army and he withdrew to his castle; I withdrew and was already at peace with him when I dropped my emissary on him_came up as "offer alliance". The Papal keep is garrisoned with 37 men good and true.
Bookmarks