The Music in Fairy Tale was written by the Greek composer Zero-Project, and it encompasses the game perfectly.
Most of the musical pieces chosen for Fairy Tale are calm, atmospheric and really thought-inspiring. It goes together perfectly well with the mod's rather aggressive and warlike world as it really sets a counterweight to all the fighting and diplomacy. I wanted that effect in my game music.
The first Zero-Project album that I found was named Fairytale, actually, which is also his latest and caught my eye, and it is from that album that the most musical material is from, but I soon found that he had made a lot of other music suitable for my mod as well, and soon started including other songs, from other albums too.
In the update to the mod that will be along in a few days or so, there are also five more Zero-Project songs included in the game. Watch out for that one! And in the meantime, check out Zero-Project's page where you can listen to all his songs, not only those presented in the mod. Enjoy these masterpieces!
Zero-Project has published an article about his music's inclusion in Fairy Tale as well.