I'm playing a singleplayer game and I went into a defensive pact with William of the Dutch.
While that agreeement was still in force, Attila of the Huns and Shaka of the Zulu decided to declare war on William. I decided to honour my defense pact and declared war on them in turn.
I have tried asking them every single turn since if they want to make peace with us (William included). But while they are very keen to make peace with me (they even offer to give me cities), they refuse to even let me request they make peace with William.
The game doesn't even let me request it as part of the peace deal, it's just greyed out with the tooltip "The leader you're speaking with has no desire to go to peace with this player."
The war is not going very well for them, another turn or two and they will be annihilated, do the Zulus and Huns really harbour such a fierce hatred for the Dutch that they would rather be wiped off the face of the map than make peace with them?