LanceOmikron 
"[@ThePonyTheorist":](/1451053#comment_6198330
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I reread the relevant passages from_*Twilight Sparkle and the Crystal Heart Spell._* Cadance explains that she was found in a forest as a baby Pegasus and adopted by some Earth Ponies from a nearby village, where she grew up. Her upbringing was a happy one due to her affinity for spreading love and compassion. But living near that same village was an evil pony enchantress named Prismia, who was jealous of the village ponies for how much they all loved each other. She also had a magical necklace that amplified her evil and jealousy (Just to be clear, Prismia's necklace and the alicorn amulet are definitely two different things). Eventually Prismia cast a love-draining spell on the village, making everypony sad.
What happens next, I'm transcribing word-for-word:
_
*Cadance decided that she couldn't let that happen, so she went to see Prismia. Luckily, the enchantress's powerful necklace also amplified the power of Cadance's love, and she soon defeated Prismia with her incredible gift of compassion. Once Prismia changed her horrible ways, Cadance was surrounded by magical energy and transported to a strange place—a place that nopony except Princess Celestia had ever been! So when Celestia discovered special little Cadance in that mysterious location, her fate was sealed. The princess brought her back to Canterlot to raise her as her very own royal niece—the special and loving Princess Cadance._
*
It goes on to say that spreading love wherever she went had always been her special talent, and that she turned two families of rival ponies into best friends as her final exam at Celestia's school of magic. Funnily enough, her transformation isn't directly acknowledged. But it clearly did take place.
Another detail of note is thatshCadance kept Prismia's magical necklace from then on up until this book (it's a plot point for the rest of the story), so it's entirely possible that she had the necklace with her when she was sent to the strange dimension.
Because COLORING!!
I reread the relevant passages from
What happens next, I'm transcribing word-for-word:
_
*Cadance decided that she couldn't let that happen, so she went to see Prismia. Luckily, the enchantress's powerful necklace also amplified the power of Cadance's love, and she soon defeated Prismia with her incredible gift of compassion. Once Prismia changed her horrible ways, Cadance was surrounded by magical energy and transported to a strange place—a place that nopony except Princess Celestia had ever been! So when Celestia discovered special little Cadance in that mysterious location, her fate was sealed. The princess brought her back to Canterlot to raise her as her very own royal niece—the special and loving Princess Cadance.
It goes on to say that spreading love wherever she went had always been her special talent, and that she turned two families of rival ponies into best friends as her final exam at Celestia's school of magic. Funnily enough, her transformation isn't directly acknowledged. But it clearly did take place.
Another detail of note is that