The lost princess [WMMAP]

What if there was not one, but two daughters Diana gave birth to?

The other baby, Athanasia's twin sister, was weak at birth, therefore she had been given as dead. But one of the few maids who were there, took her and disappeared. The other people though she was dead, therefore there was not a search made to look at her.

But as the years went by, and Athanasia's coronation passed by, a letter as old as the years went by was found in one of the rooms that had not been cleaned for a long time, revealing how a maid took the other princess.

[This is just a fan fiction from the manhwa 'Who Made Me A Princess' therefore the characters are not mine.]