Persia attacked the Mamluks and gained lots of territory in that war. They also gained from Najd, who signed a separate peace with Persia. What's the point of being in our alliance, declaring war on your own and then not waiting for us to sort things out, he Najd?
Well, we make peace with Oman, vassalising them.
Then a white peace with Persia is signed, as we have no better idea what to do to them.
Venice meanwhile refuses to become incorporated into the Vatican Empire. Drat, and we had a "maybe" chance even! But take a look at that Burgundy army. It's large, but only at 50% strength...