User blog comment:Chawk1993/Arthur and Morgana Confrontation in Sword in the Stone part 2/@comment-5036924-20111231114542/@comment-5036924-20120101150639

Shoving it in added nothing but a nightmare for me, unfortunately, and I can never see it as a good twist. It's basically due to the fact that I knew nothing about the legend before I started watching, so there I was starting S1, quite young and totally ignorant about Arthurian legend (genuinely had NO idea about Arthur and Guinevere or Morgan/Mordred etc), and I got so sucked in by Arthur/Morgana that it meant seasons of frustration and disappointment when it all went in completely the other direction to what they were setting up in S1. So I can never think of throwing in the sibling thing as a positive, sadly.

I think it would be perfectly reasonable for Arthur to either refuse to accept it or try and forget about it. It would presumably be so disturbing to discover a woman you used to flirt with was in fact your sister that it wouldn't be irrational to deny it. And in any case, the only thing anyone has to go in is the fact that Uther thinks Morgana is his daughter, which in turn makes her claim to be his daughter. If you think about it, surely a) that's fairly shaky evidence for everyone else and b) nobody can be completely sure Uther genuinely fathered Morgana even if he did have an affair with Vivienne.

But then that's just me looking for loopholes in the whole thing.

I think she may well have been there even if she hadn't overheard Uther. There's more than one way to win a throne and if inheriting it wasn't an option she and Morgause may well have simply gone for the murder-and-grab ruse.