After the Elements free her from Nightmare Moon, Luna asks Celestia, "What happened to my daughters?"
Celestia escorts Luna to the Canterlot sculpture gardens and shows her the Reliquary of the Heroes.
Under the statues of her millennium-dead daughters, Luna learns how they lived in the shadow of Nightmare Moon's treason, and how they died as glorious heroes of Equestria.
Not related to any of my other stories.
Content warning: Pandemic. Note that this was published before current events.
Wow! Made number 7 6 5 4 3 2 in the feature box! Thanks for the upvotes, everypony, and I appreciate the comments!
Feature box 2019/05/06-09!
Update feature box 2019/05/28 and 2019/08/05!
I love you all, everypony!