Castle of The Two Sisters, 20 years before Nightmare Moon.
The castle was abuzz with activity as servants rushed to and fro and a loud scream echoed throughout the long hallways.
The Princess of the sun, Celestia rushed down the hallways almost breaking into a gallop towards her destination, her assistant had just informed her of the very news Celestia had been waiting on for days now, her sister, Princess Luna diarch of the night, was entering labour.
Celestia's thought pattern raced a billion miles-an-hour as both excitement and no small amount of nervousness fell over the solar diarch. Ultimately her thoughts fell on the Pegasus stallion who should have been here to see this, Night Rider would have made a brilliant guard captain and would have made an even better father... if only it wasn't for those damned Griffons and their border skirmishes...
Celestia came to a halt as she reached the infirmary doors, inside she could hear Luna in so much pain and yet she froze, unable to decide whether she should enter or not.
One voice, or rather Royal Canterlot Voice, however, made that decision for her
"WHERE IS THAT DAMNED SISTER OF MINE?!"
So now it was obvious Luna wanted her support so Celestia did the right thing and promptly flung open the doors, swiftly entered the infirmary and went to her sister's side. There were doctors and nurses buzzing around the place with one constantly telling her to 'Push'.
"It's OK Lulu, I'm here," Celestia comforted her sister.
"WHERE HAVE YOU BEEN?" Luna shouted in her Royal Canterlot Voice, again.
Celestia suppressed a slight giggle, "Now now Lulu, you don't want to deafen the poor foal moments after the birth!"
"Ha ha very funny Tia..." Luna said, grimacing in pain.
For what seemed like hours Celestia sat at her sister's side comforting her, helping through the pain that came with the miracle of childbirth.
And then at long last, it was done...
"Its a filly!" Shouted one of the doctors delivering the small form into Luna's waiting hooves.
"She's beautiful..." Luna smiled with tears of joy welling up in her eyes.
Celestia observed the small filly in Luna's hooves. She was a beautiful lavender coated Alicorn filly with a dark purple mane and tail with a pink stripe going through both. The filly opened her eyes which were the same colour as her coat, before closing them and going to sleep.
"That she is Luna, what will you name her?" Celestia asked, giving her sister an affectionate nuzzle.
"Myself and Night Rider..." Luna paused slightly at the mention of his name, but she quickly continued, "We had discussed names for if it was a stallion or a mare, we never could decide on a male name but the female name we decided on pretty quickly..."
Luna nuzzled her daughter for the first time.
"Twilight Sparkle."
im sorry just his name makes me think this
why do people keep thinking Twilight's mane is purple. It's a dark blue
Would Luna even go the nightmare route if she had a daughter? It would really change up the dynamic.
The gender terms for foals are colt and filly. Stallion and mare are for the fully grown ones.
You write Doctor Whooves stories??
/me goes to check them out.
MLP and Doctor Whooves introduced me to Doctor Who.
EDIT: after I read a bit more of this one of course!
6388715 They say "lavender aura" all the time too, even though it's magenta like her cutie mark.
Good start, but I noticed some little errors:
Should be "it", as in "it was obvious".
Should be "her sisters side."
Two here. After "I'm here" there should be a comma, as in, "I'm here," Celestia comforted...".
And you're missing a period at the end. :P
Comma after said, as in, "Luna said,"
Another possessive. Should be "her sisters side."
The description of Twilight should be made into a new sentence, with no comma. An example:
Celestia observed the small filly in Luna's hooves. She was a beautiful lavender coated alicorn filly with a dark purple mane and tail with a pink stripe going through both.
Also! Twilight's mane is dark blue in the show, not purple. Just saying.
Should be a comma after asked, as in "Celestia asked,"
Should be, "Me and Night Rider..."
I know this is the first chapter and you have a dozen already published after this, but I hope it helps.
Sorry if I'm being picky. ¯\_(ツ)_/¯
I guess you could say that Night Rider really...
*puts on sun glasses*
... rode the night.
6539804 oooohhhhh shiiiiitttttt!!!

6539804
Okay you have my attention go on!
Poor Luna, giving birth to a full grown, adult pony
. Most ponies give birth to fillies and colts, not mares and stallions.
I just read this chapter after reading the final chapter of Change so forgive me if I'm wrong but, is it just me, or do you like "twilight past being complete shocking turn of a events" as much as I like Scootaloo becoming a superhero, like the time she became The Champion of Magic, or the time she became The Entity of Hope.
6539804
something about this reminded me of a fan-comic on DeviantArt called "to love god-to love mortal" by Vavacung, involving Celestia's long-dead lover, Victory Wing, who has been re-incarnated as a filly named Paper Mache.
but it's a rather tragic story...
9144823
I remember that story, it was alternate universe to the events of the actual show: after discovering Paper Maché, Celestia would leave her role as Princess of Equestria to hide amongst the populace in order to get closer with Paper. Luna would become the sole ruler of equestria until Nightmare Moon returned... and helped her poor friend in juggling all of the government paperwork that Celestia left behind.
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Hey I know that story too!
9144823
I also know it too!
I love these Luna/NM is the mother of Twilight stories as well as "Past Sins" even though that technically Twilight mother of NM. They simply have a good dynamic in my opinion.