Hidden Noble Rank was a term used by the Reverend Mother Proctor Superior of the Bene Gesserit Sisterhood to indicate that an individual's true highest rank within the Sisterhood could not be publicly identified.
The best-known Bene Gesserit Reverend Mother Proctor Superior of the Hidden Noble Rank was the Lady Anirul Corrino, the beloved wife of the Padishah Emperor Shaddam Corrino IV. After her tragic death on the planet Kaitain, she was succeeded by her eldest daughter, the first-born Imperial Crown Princess Irulan Corrino.
Behind the Scenes Edit
Frank Herbert never expanded on why it was necessary for someone from the Bene Gesserit Sisterhood to have their noble rank hidden.
It was possible that the Hidden Noble Rank was used when a person's standing within the Sisterhood was so high that it was necessary to keep it secret, especially if somebody else was still married to the Padishah Emperor of the Known Universe and became the mother of his Imperial heirs apparent.