First contact. Not just with a new world, but with a world in a whole new universe. Initial negotiations go well, so Princess Celestia makes a visit to this 'Earth' to cement peaceful relations. Unfortunately, even when you are as experienced as the goddess of the sun, it's the little things that can trip you up.

Preread and edited by Noe Carrier. SPOILERS IN COMMENTS!
Russian translation: Все это скоро закончится, принцесса by Smikey

In the far reaches of Canterlot Castle, high above in the towers lived the archmage. Everypony knew her, yet few had met her.

Twilight Sparkle sighed, having teleported away another noble seeking favors before reaching the top of the stairs for the second time today. They never learned. As the archmage, she already dealt with political squabbles far too often without inviting them into her home. Aside from personal favors for Celestia, she did what was required of her position and then returned to seclusion and research.

The nobility grumbled that no archmage should be a commoner, and Twilight’s disrespect toward them proved it. Each and every time they were forced to bow to her, they hated what they saw: the position, the status, the deference.

Was she not powerful? Was she not great?

Twilight, now reading through dusty scrolls and long forgotten tales, wrote in her notes — notes gathering dust of their own. A brief thought flashed through her mind.

Am I not powerful? Am I not great?

And then Twilight picked up The Tale of the Royal Pony Sisters.

Defunct side stories told in Across the Boundary. They can still provide a little context, but when in doubt, the main story here is canon.

Cover art provided by Lafiir

The sequel to this story: Sweetie Belle and the Quest for Knowledge is now available!

When Sweetie Belle finds a mysterious artifact of a now lost civilization, how will she come to terms with the wealth of knowledge it provides? It says it can be ignored, it says it will never try to influence her, but can an artifact of such power really be so harmless?

Book I of III

Prologue and Chapter 1: Thanks to TheOtherSideOfFluttershy for pre-reading and editing.
The whole story: Thanks to RaylanKrios for editing.
Chapter 4: Thanks to AuthorGenesis for editing.
Epilogue:
Thanks to Malefactory for editing.

SF (canon species only; no humans) Ponies were magically and genetically engineered to be the perfect servitor race. They are powerful, adaptable, intelligent and completely under the control of their creators. A laboratory accident frees one such pony from her mental chains, but how can one mare save herself and the rest of her kind if she doesn't even know she's a slave?
This is not the Equestria you know and these are not your little ponies... not yet, anyway.

Tags: Adventure, Diamond Dogs, Gryphons, NO HUMANS (did I mention that already?)
Other tags: historical, mind control, Clarke's 3rd Law, excessive use of high energy physics, before they were famous.
Detailed review by PaulAsaran.
Cover art by endrome , used with permission.
Russian translation (partial -- 'unofficially' completed in the comments)
A Soot-Covered World, book 1.