Everypony knew the Solar Court was where you went when you absolutely, positively needed the throne to hear your case.
Like much of what everypony knew about alicorns, it wasn't exactly accurate. Princess Cadence just needed to land on Celestia's balcony at the right time. "Where is it, Aunt Celestia?"
Celestia looked up from her desk and smiled. "Cadence! How nice of you to visit."
That got a roll of the eyes as Cadence stomped into the room, wings still flared out. "Yes yes, family reunions, love and happy fuzzy feelings and all that." She thrust a forehoof in her aunt's face. "Now hoof it over."
After a moment of blinking at the appendage, Celestia said, "Hoof what over, dear niece?"
"Someone stole the Crystal Empire's Declaration of Independence, and the tallest alicorn princess in the known world wearing a fake moustache can only stump my guards that long before they figure it out." Cadence narrowed her eyes. "Now give it back."
Celestia didn't so much drop her innocent mask as lift it with a single eyebrow. "You do realize that you're my adopted niece and your husband is directly related to Princess Twilight. A piece of paper will hardly actually make the Crystal Empire independent from Equestria."
Cadence matched her flat look for flat look. "Our main exports are crystal berries and crystal wool. If there was any danger of actual independence I wouldn't have signed the blasted thing. Now give it back; that scroll is one of maybe five things in our museum that doesn't make my subjects depressed."