Board Thread:Wiki-Related Discussion/@comment-5679696-20141027232348/@comment-24674051-20141104150452

And also, who's to say that both Idun and Gerda aren't correct. Another part of the OUAT canon is that when Helga and Ingrid went missing, they had Pabbie memory wipe the entire kingdom. It is possible that, to maintain the illusion, they also changed Gerda's name to Idun. Because, as we saw with the family tree at the police station, even memory wiping the entire kingdom did not remove all of the written history of the 3 sisters.