Displeased with her tutelage under the princess of the sun, Sunset Shimmer leaves through a mirror deep within the vaults of Canterlot. With her trusty companion Philomena by her side, Sunset steps into a new world. But not the one the book said it would be. A small calibration error will leave two worlds of magic irrevocably changed.

A crossover with the Harry Potter books and a Sunset in Hogwarts story.

Now with editing courtesy of Rainbow Sparkle

[Complete! With TVTropes apparently!]
Also, apparently, an animated trailer.

In a world of brass and steam, Twilight Sparkle had thought she had made a life-changing discovery with the invention of the telescope. For better or worse, she was correct.

Now her discovery has not only changed her life, but the lives of those she seeks out in her desperate attempt to contact the only other creature as lonely as Twilight herself.

It all would have been much simpler, but it had to be the one Twilight could only call The Mare on the Moon.

Decidedly not within walking distance, then.

[Featured on EQD before story was meant to be submitted. 4/03/2015]

[Editing team: Southpaw, Wolfvenom, Maskedferret, SwanSong and BluePaladin42, without whom this story would be a fraction of its current state.]
[Special thanks to Novel-Idea for the updated cover]

To better herself, Luna has studied Twilight's actions and friendship reports almost religiously. However, she never expected to find the tables turned and be under the microscope herself, nor did she realize that a pony would go so far for one they called friend.

Pre-reading/editing by auramane, Habanc, Foals Errand, Meridian Prime, and Timaeus

Cover art commissioned by me and done by Silfoe and can be found here. Thanks a bunch!

Celestia is trapped on Earth.
Not as a human. Not as an alicorn. She's a common horse, an Arabian mare, without her magic, voice, knowledge of the language - not even freedom, forced to work at a riding school.

What can a single Arabian mare do to get back to Equestria from this backwater European country? With only the mind of a princess and a pencil in her teeth, Celestia must find a way home.

[Illustrated] [Alternate Earth] (without Bronies)
Rated Teen for language and some scarce suggestive themes.
Proofreading by AlicornPriest

Polish language version

This story is a sequel to Princess Celestia The Changeling Queen: Stories Behind the Mask

At the Royal Wedding, Chrysalis and the Changelings were revealed to all of Equestria.

But another mask was torn away that day. A mask born for a thousand years. A mask created on one promise. A mask, that has become synonymous, fused, to its bearer.

A mask that when ripped off, causes Twilight, her friends and Luna to question everything they ever knew about the one pony, one very important pony.

At the Royal Wedding, the meaning of the phrase 'Princess Celestia' changes forever.

NOTE: Chrysalis is NOT Celestia!!! That'd be impossible to pull off.

Credits to: Plainoasis for the design of the cover art
Note 2: Original cover art here: https://angelea-phoenix.deviantart.com/art/Contest-entry-Changeling-Celestia-337023552

Pre-read/edited by Zervziel,
Blankscape,
FinalFan,
Courage Fire
Aurora Borealis

Side Stories to this can be found: here.

An audio-reading on youtube up to Chapter 21 is up by StraightToThePoint Studios. I'm aware there are others but this is the nearest complete one: [embed]https://youtu.be/X3eMW673CSY[/embed]

There are also 2 print versions of Princess Celestia:The Changeling Queen. Nonexistent Publications run and Ministry of Image's run.

Contribute to the TV Tropes Page (thanks to Babs_Seed72 for getting it up)

Harry Potter was a lonely boy who one day wished for a friend. Luna, trapped on the moon, wished for the same. And so their wishes are granted. How will the two deal with each other? And what about Nightmare Moon? Needless to say, their lives are going to change in both expected and unexpected ways...

Other stories in the Lonelyverse:
Hooves, Plush, and Magic: The Untold Tales
The Wizard and the Lonely Princess: Hallowe'en Special
A Nightmare Christmas

Chapters 9-11 now re-written.

For a thousand years, the Code of Harmony has ruled Equestria, and the Code of Dissonance has sabotaged its works at every turn. Now the war for control over the land will come to a head, and one unicorn's decision may decide the fate of all.

For though she does not know it, Twilight Sparkle is the shining example of the Code of Harmony. Her teacher, Princess Celestia is Harmony's most powerful master and she knows her enemies are hatching a plan that threatens to cast down the Harmony of her throne and all she has sacrificed to create.

What she does not know is her foe seeks a new Apprentice to turn to his dark ways. A unicorn with seemingly limitless potential for magic, whose thirst for knowledge may yet lead her down a dark path, who is known to be such a faithful student of magic, eagerly seeking the truth no matter how forbidden it might be...

Sequel: Code of Harmony

This story is a sequel to The Celestia Code

When the monsters created by the dark crystal engine escape their prison, it's up to Princess Twilight Sparkle to deal with them. She gets help and advice from Princess Luna, but things don't go as planned. In fact, when a pony who relies on logic and rationality tries to navigate the stormy seas of emotional entanglement while simultaneously saving Equestria from a horde of evil creatures intent on destroying everything they encounter, nothing goes as planned.
AUDIOBOOK by VisualPony
WARNING: Major spoilers in the comments.

Book 2 of the Alicorn Adventure series.

Goodreads Page
100% Approved by Twilight's Library!

The Badass Twilight tag applies more than ever, but please note the new tags.

This story is a fairly direct continuation of The Celestia Code. You might be able to follow it without having read The Celestia Code first, but it's better if you do.

The sequel is here: The Twilight Enigma

Most excellent pre-reading/editing done by the erudite AcademicPony and the dapper statoose!

Twilight Sparkle has too much magic, and it will take her decades to learn to control it. Her spectacular loss of control during her entrance exam only proves that fact. She is a danger to herself and others.

After Sunset Shimmer’s disappearance, Princess Celestia needs a new student to bear The Element of Magic to defeat Nightmare Moon. With all of Equestria at stake, Twilight Sparkle…is not the pony she needs.

Princess Celestia seals Twilight Sparkle’s magic with the distant promise of one day teaching her.

But there are two diarchs of Equestria. Amidst a lucid dream, an offer is made.

“Hello, Twilight. Would you like to be my student?”

Cover art provided by Lafiir.