Talk:Twilight's Kingdom - Part 2/@comment-25270260-20140809233534/@comment-24908786-20140810145940

Not to mention that Tirek never brought up what he did to Celestia, Luna, and Cadance, after taunting them about transferring their magic to another pony so they only prolonged the inevitable.

For all the Mane Six, especially Twilight, knew, the other Princesses and Shining Armor were still in Canterlot, and although we see Twilight and Rarity as they return the unicorn magic to Shining Armor and the unicorn Royal Guards, I don't think they even noticed the empty throne room where Twilight last saw the Princesses. She probably even thought that they went into hiding in the caves underneath Canterlot from A Canterlot Wedding until Tirek was defeated.