Princess Cadance is featured in the chapter book Twilight Sparkle and the Crystal Heart Spell.[9] The book tells the story of Twilight Sparkle after she'd been made an Alicorn and seeks advice on being a princess. She turns to Cadance, who tells her life story, how as a baby Pegasus she was found in the woods by Earth ponies, who took her to their village. When she grew up she reversed a love-stealing spell cast by a pony called Prismia. Prismia wore a magic-enhancing necklace that amplified her evil and jealousy, but when Cadance confronted her, the necklace amplified Cadance's love. Once Prismia changed her horrible ways, Cadance was surrounded by magical energy and transported to a strange place where she met Celestia, who adopted her as her royal niece.

cf :Twilight Sparkle and the Crystal Heart Spell sur le wiki

"Premièrement, je veux juste dire que je ne peux même pas croire que Luna et moi allons être des princesses ! C’est arrivé si rapidement et de façon si inattendue. Un mystérieux mage licorne qui disait s’appeler Star Swirl le Barbu nous a approché. Et quand je veux dire mystérieux, je ne veux pas le dire de façon méchante. Tout d’abord, il s’est présenté comme “le Barbu” de façon honnête car il a la barbe brune la plus longue que j’ai jamais vue ! Ensuite, il portait un grand chapeau et une cape de magicien avec des motifs d’étoiles et de lunes dessus, et il y avait des dizaines de cloches sur les bords qui tintaient et sonnaient quand il marchait. Je pourrais le retrouver très facilement dans une foule ! Star Swirl et ses compagnons -- Smart Cookie le poney terrestre, Private Pansy le pégase et son apprenti Clover the Clever, la licorne -- nous ont tout raconté sur les différends entre les différentes espèces de poneys. Depuis que les trois tribus étaient parvenues à s’entendre et avaient fondé Equestria, elles souhaitaient avoir des dirigeants pour préserver cette paix, et c’était pour cela qu’elles avaient fait appel à nous.
Ils savaient que les alicornes étaient les représentations des valeurs d’Equestria: l’amour, l’harmonie et l’amitié. Et puisque les alicornes sont des combinaisons des pégases, des licornes et des poneys terrestres, ils pensaient que nous pouvions représenter les citoyens d’Equestria de la meilleure des façons -- tous les poneys égaux à nos yeux. Ils nous avaient donc demandé d’être leurs princesses.
Et c’était vraiment très gentil, mais ça reste quand même très impressionnant! Je veux dire, Luna et moi sommes très honorées. Comment ne pas l’être? Ce n’est pas tous les jours qu’on vous demande de diriger un pays entier. Cependant, Luna et moi avons affirmé que notre rôle en Equestria ne serait pas de la diriger, car nous ne considérerions pas les poneys d’Equestria comme étant nos sujets. Cela serait bien trop bizarre. Nous serons les gardiennes d’Equestria. C’est beaucoup mieux comme ça. Nous servirons et protégerons les cieux comme les plaines, maintenant la paix et l’harmonie."
[align=right]- Celestia, extrait d'une traduction fanmade de la 1ère entrée du journal des Deux Sœurs.[/align]

"Dear Diary,

Because Alicorns age at a different rate than the rest of the pony races, Luna and I don’t have our cutie marks yet. Being a “blank flank” at our age never felt unusual. I’ve always known that I would get my cutie mark at the proper time. But now that we are surrounded by so many ponies who have their cutie marks and are so much younger than we are, I must admit, it feels a bit odd.
Hopefully now that we are princesses, Luna and I will find our true calling and finally get our cutie marks.

Celestia"
[align=right]- 4ème entrée du journal des Deux Sœurs[/align]

"[...] But the most magical moment came when Star Swirl stepped up with ten other Unicorns. Using their Unicorn magic, Star Swirl and five of the Unicorns focused their energies and brought down the sun. Star Swirl when joined the other five Unicorns, and using all their concentration, he guided them in raising the moon. It was truly amazing and took a huge amount of powerful magic. Luna and I watched in complete awe."
[align=right]-Celestia, extrait de la 3ème entrée du journal des Deux Sœurs[/align]

"[...] As Luna and I had seen, six Unicorns are required for the task of raising and lowering the sun and moon every day and night. Star Swirl was always one of the six for both the rising and the setting. But it takes a powerful amount of magic, and what nopony told us was that the Unicorns who volunteer for the job can only withstand the task for a short period of time before their magic is completely depleted… forever. Star Swirl himself had been the only Unicorn with strong enough magic to withstand this process day in and day out, night after night. But ten other Unicorns constantly needed to offer up their magic as a sacrifice for all of Equestria. This morning they ran out of full-grown Unicorns with magical abilities and were unable to perform their task. When Star Swirl tried to lower the moon by himself, he was unable to, his magic was depleted, and his beard turned gray.
Luna and I looked at each other, mortified. Why didn’t Star Swirl come to us sooner? Why didn’t he tell us this was happening to the Unicorns? And what could we do to help? Star Swirl’s eyes brightened. He clearly had an idea. As we knew, Alicorns possessed a level of magic far beyond anything a Unicorn could ever imagine. Raising and lowering the sun and moon wouldn’t cause us any harm. In fact, if the myths he’d read were true, it would actually rejuvenate us, making our magic that much more powerful. Then, as if he even needed to say anything more, Star Swirl asked if, as princesses of Equestria, we would be willing to be the new guardian of the sun and moon."
[align=right]- Celestia, extrait de la 32ème entrée du journal des Deux Sœurs[/align]

"Of all the stories I heard on our travels, the one about the founding of the Crystal Empire is my favorite. See, the whole reason the Crystal Empire exists is because of the Crystal Heart. When the Crystal ponies found that Crystal Heart, the young Unicorn Amore found her true calling. As a pony who was always full of love, she felt an immediate connection to the Crystal Heart. Amore projected the positive energy within her into the Crystal Heart, which then magnified that love, sending it over what would become the Crystal Empire. Amore immediately got her cutie mark of a crystalline heart and became princess of the Crystal Empire. From that day forward, the Crystal Empire was protected by love emanating from the Crystal Heart."
[align=right]- Luna, extrait de la 29ème entrée du journal des deux Sœurs[/align]

"Celie and I were very respectful when Star Swirl introduced King Bullion and Princess Platinum. But when our introductions were made as the princesses of Equestria, that little upstart turned up her muzzle, rolled her eyes, and claimed she didn’t understand why Celestia and I were even needed. After all, she could have been the princess of Equestria herself. Why didn’t anypony ask her?
I couldn’t believe it. If somepony like Princess Platinum thinks she can behave that way with anypony, let alone me, she is sorely mistaken. So I busted out my loudest and most terrifying Royal Canterlot Voice.

“Princess Platinum! Darest thou treat the princesses of Equestria is such a manner? We are not amused! Thy behavior is disrespectful. Ill befitting of one in thy position and reflects poorly upon the Unicorns thou art representing. Perhaps thou shalt be stripped of thy crown and thy title?” "
[align=right]- Luna, extrait de la 13ème entrée du journal des Deux Sœurs[/align]

"Princess Platinum even designed our official seal for the Equestrian flag to fly on the top turret outside out castle. She said she was having more flags made for all of Equestria. I’m so glad that Princess Platinum has realized that Luna and I are here for all of Equestria, including the Unicorn Kingdom, and has come around to being our friend."
[align=right]- Celestia, extrait de la 14ème entrée du journal des Deux Sœurs[/align]