[Emperor's Child]

I think I've been only trying to go to a grade agreement first, I hadn't thought about starting with a Non-intercourse agreement.

It's probably exactly it: there is a unwritten sequence of getting out of war that starts at NON-INTERCOURSE and works its way up from there along the list. It's the same thing as you never get a Trade and research agreement without first having a trade agreement, military alliance without first having a trade and research alliance, etc.

Thanks!