There's been a discussion about Something The Last Battle and Prince Caspian Have in Common, which I actually kind of get. But is there anything that The Horse And His Boy and The Last Battle have in common?
Well, they both feature Calormenes, that is one thing. I think another that both stories don't start out in our world, like most of the books in the series do. We don't see our world at all in The Horse And His Boy and we only get a glimpse in The Last Battle. I think another could be that both feature villains that want to conquer Narnia (Rabadash and Rishda, that is).
Do The Horse And The Boy and The Last Battle have anything in common, perhaps more than we think?
"And this is the marvel of marvels, that he called me beloved."
(Emeth, The Last Battle)