Cadance

With the release of the latest issues of the comic, I think it's time to put up the portraits of two other members of Twilight's family. I admit to being curious to Cadance's history... I understand one of the tie-in books to the show revealed that she was originally a pegasus who "ascended" or whatever to alicorn and princess status much like Twilight did (albeit not through completing a spell). But where did she come from? Was she always in Canterlot and just unmentioned? It's surely not a coincidence that her cutie mark is the crystal heart, and that she has the same sheen to her hair as the crystal ponies do, despite not sharing their general "crystalliness". But how does she tie in to an Empire that had vanished 1000 years ago?