User blog comment:DragonsHaveMoustaches/Why did Gaius take Morgause to the High Priestesses?/@comment-5209013-20120625084107/@comment-5209013-20120629112524

Thank you for your question! I'm sorry for my late reply, I just graduated and have been rather busy during the past few days.

I know it is said on Vivienne's page that she was a lady-in-waiting for Ygraine, but I don't think that has ever been confirmed. I believe it is something the fans came up with.

I'm afraid we don't know anything about Vivienne, apart from the fact that she was married to Gorlois and is Morgana's (and most likely also Morgause's) mother. We don't even know whether she's still alive or not! (I'm kind of hoping that she is, and that she will rejoin Morgana in the fifth series).

But, as you said, it is indeed very possible that the marriage between Vivienne and Gorlois wasn't out of love, as she had committed adultery with Uther. Therefore, I believe she must've been of noble birth and given in marriage to Gorlois. Or maybe the High Priestesses knew that Vivienne's daughters would have a destiny to fulfill, and therefore sent her off to marry Gorlois, as it is a part of the future they'd foreseen?