“By Celestia’s beard!”
 
That’s right folks, THE HINTS HAVE BEEN THERE ALL ALONG!

he couldn’t because he can’t become a princess

“Wait,wait Princess Celestia…you were once Starswirl …a stallion?”  
“That correct Twilight.”  
“!b-But how? “  
“Well I too was the student of an Alicorn,her finest like you ,and like you I had proved that had the skill,knowledge and will to lead the ponies of Equis to dominance over the other races and bring about a glorious “shining golden era”… But there was one problem…”  
“ you- you never understood the magic of friendship~~”  
“NO!I had a penis”  
“…uh”  
“Yeah only mares can become Alicorns so…she used her magic to make me a SMoking hot Alicorn with a virgin white coat and pastel hair female…but yes feeling the universe take your sclong is not fun,not fun at all…  
“But~~ but what about luna!  
“Oh her ,she got off easy was born a mare ,no “mareafication”for her but even though I’m now a multi thousand year old horse with magic hair ,I still have the mind of a stallion.”  
“Oh ..really”  
“Yup so remember that time you showed me that dance you and my delectable niece made?  
“…uh-huh…”  
“That was hot”  
“…0///0

Hello Pony of Shadow– I mean Starswirl.

@Prof.NightJack  
yeah, Hero by All Insane Kids

@LightDark  
Isn’t that a song from the ending day of Bionicle?

Do you know what it take’s to be a hero?  
When you lost, a piece of love, a piece of you.  
Do you have what it takes to beat the fear that’s  
In your heart, to grow up strong, and redo wrong.  
To grow up strong, and undo wrong