User blog comment:DragonsHaveMoustaches/Why did Gaius take Morgause to the High Priestesses?/@comment-5191335-20120625061807/@comment-5209013-20120625074243

Thanks a lot for your reply! It was really interesting to read. They are all good, plausible theories.

About Vivienne and Nimueh, correct me if I'm wrong but I believe Nimueh was supposed to be immortal (as in 'she didn't age', she stayed young forever). It is, however, really interesting that she and Vivienne were supposed to be the same person in some legends. Perhaps the writers purposefully mixed them up? (possibly symbolic - they symbolise the Old Religion - as Iwould personally find it very odd if Nimueh would be Morgana and Morgause's mother).

As for Morgause being a sickly child, that might indeed clarify Uther's reaction why he believed she had died (as Fimber has said earlier, we indeed do not know if he really ordered her to be executed). Gaius might've taken her to the High Priestesses to heal her, but then I don't understand why they told Uther that Morgause had died (Uther couldn't have been weary of the High Priestesses back then, Nimueh was a High Priestess herself and served at his court).

I don't think it is ever said that Morgause was illegitimate. It is, however, possible as we don't know who her father (and we're not even sure whether Vivienne is her mother) is. The fact that Gaius, before Uther's confession that he is Morgana's father, thought that Morgana and Morgause were merely half-sisters means that they could either share the same mother or that they are not related at all. The bracelet might indicate that Gorlois is indeed Morgause's father, as it bore his symbol, but Morgause said in the 'Sins of the Father' that it was a gift from her mother, and in 4.07 (The Secret Sharer) Morgana claimed that the bracelet was forged at the Isle of the Blessed. It doesn't make sense!

I think the writers have dragged themselves into a massive plothole and have therefore decided not to clarify it anymore.