Twilight walked into the throne room. The princess had sent her a letter, asking her to come to Canterlot and speak with her. As she walked into the throne room, she admired the massive stained glass windows. All of them showed scenes of great moments in Equestrian history. She stopped in front of one of them, it depicted the princess raising the sun. The window faced perfectly so that the morning sun hit the sun depicted on the glass so that the entire room would light up looking as if the light came from the sun on the window. As Twilight admired its beauty, she failed to notice a figure walking up behind her.
"Admiring the scene?" Celestia asked her.
"Oh!" Twilight was slightly startled, "I didn't see you there... I'm sorry for keeping you waiting."
"It is no trouble. Do you know the story behind this window Twilight?"
Celestia waved a golden clad hoof at the painting.
"No, i have seen it many times before, but i never knew there was a story behind it." she looked at the Princess in curiosity.
"Every window here has a story, this one is particularly close to myself."
"Why is that Princess?"
"it depicts the first time I raised the sun in the morning, it was the day after my sister and I came to the throne."
"I was always told that you were always in power, are you saying that someone else ruled before you?"
The princess looked down at the pupil. She was saddened by the look she saw on Twilight's face. For reasons she could not explain, the genuine curiosity on Twilight's face made her feel a longing. She could not quite put her hoof on it, but she felt a need.
"My sister and I were not always the rulers." She sighed as she said it.
Twilight noticed the sigh and the saddened look that crossed the face of the equine ruler.
"Princess is there something that you want to talk about?"
The princess realized that she had let her guard down long enough for Twilight to notice.
"You are likely to not understand."
"But it might make you feel better, Princess. You have confided in me before, is there something wrong?"
The Princess decided inside herself, now was just as good a time as any. She was lucky that Twilight began to look at this window. It gave her a perfect springboard to tell Twilight what she had called Twilight to Canterlot to speak with her about.
"I am old Twilight. I may not look my age but I can feel it. I have lived for thousands of years, as has my sister." she began. "I am not immortal, Twilight, I can still die. I can be killed just as easily as any other pony. Disease, hunger, tiredness all affect me. I am not a goddess, as much as I sometimes wish I could be. I am just an Alicorn. I simply age at a much slower rate than other ponies. I remember when I was a foal. Our mother, Mystery was her name, used to tell us, ' Luna, Celestia, one day you will take over for me, you will raise the sun and moon for all of Equestria. and when you do, remember me because I love you and I want you to be happy.' She used to let us sit on her throne, pretend that we were the princesses, I miss that me, Twilight. What happened to the Celestia that had fun? What happened to the Celestia that was intrigued by new things. I used to be adventurous. But time took it's toll on me, and I no longer have the will to do what iI used to. I see so much potential in you. I see myself in you. You show me how I used to be. And my time is coming to an end, as is Luna's. She and i both know this. Thats why I asked you to speak with me privately today Twilight. Luna and I have discussed it and we came to the same conclusion. Twilight Sparkle, I want you, to be my heir to the throne of Equestria. Luna is on her way now to speak with Rarity. Luna believes that Rarity would make a suitable replacement for herself."
Twilight looked dumbfounded. She didn't know what she could say in response, so she simply said nothing. She looked back at the window, her mind mulling over what she had just heard. The Princess wanted her, Twilight wasn't even fully grown herself, to rule Equestria when she was gone. Twilight put her hoof to her mouth in realization that the princess would, in fact, have to be gone in order for that to even happen. She looked back at Celestia saddened by that fact. Celestia gazed back at her seemingly waiting for a response.
“I...I don’t know what to say, except that I’m honored.”
“Will you do it?” asked The Princess.
“I don’t know how that would work. It can’t work. I’m a unicorn, I have magic but your an alicorn who lives for thousands of years. I can’t be expected to live that long, its not possible.”
“Twilight,” began Celestia, “Do you know the story behind how Luna and myself became the rulers?”
“No, princess, I don’t” Twilight responded.
“Its not a big surprise, nopony lives that remembers the tale, apart from Luna and Myself.”
Celestia thought about it for a moment before starting again.
“Perhaps we should wait for Rarity, she will do doubt have the same questions as you. It would be more efficient for Luna and myself to tell you both at the same time. Follow me, i will tell you all in my personal chamber.”
Celestia lead Twilight through the corridors of the Castle before finally stopping at a large door. it was wooden, no different from many of the doors, save for a small round hole in the top. Celestia motioned to the guards outside the chamber and they backed away. She then placer her horn inside the hole. The outer edges of the hole began to glow, small lines of light began to snake and twist from the edges until a clear shape could be seen. It was the Princess’s cutie mark.
“Nopony apart from me or Luna has ever entered this chamber. At least not for the last ten thousand years.”
The door opened slowly, creaking like an old door that has not been opened in a very long time. Celestia motioned for Twilight to walk inside.
Inside was a large room, circular in shape, the floor was carpeted with colors that formed Celestia’s and Luna’s cutie marks shaped together in a sort of Ying-Yang symbol. the ceiling was domed, at its peak was a large skylight in which the light entered the room. As with the window in the entrance hall, the window here was made so that the light from the sun at midday would shine to illuminate Celestia's cutie mark on the floor. Twilight guessed it would do the same for Luna’s at night. On the walls there were two paintings, one of each of the pony sisters. on either side of the room were doors. Each of the doors had a name written above the door, one for Luna and one for Celestia. Twilight assumed these were bed chambers. In the middle of the room was a small area for sitting and relaxing, while the rest of the room was rather empty.
“I feel honored that you would consider me for this.” Twilight began but the Princess walked off, opening the door with her name above it. She turned and looked at Twilight.
“Twilight, I want you to stay here, until I get back. I am going into my room to remove the royal jewelry. I don't want you to feel like i am the princess right now, i want you to feel like I am talking to you as a friend.”
With those words she walked into her chamber and closed the door.