User blog comment:OneofthePendragon94/Does someone know what happened to Morgana's mother Vivienne?/@comment-4650675-20130101204713/@comment-5102537-20130102103941

"...although it would be cruel from Uther's part to murder his daughter's mother in cold blood, I would actually expect it from him-he did not spare druid children, why should he have spared a high priestess?"

Yes, but the druid children weren't close to him. He spared Gaius and even considered him as a friend. He even spared Nimueh for some unknown reason. That's what I always thought was contradictory to all the things we later saw of him. The show runners put more and more cruel actions on his character later when they created the story of killing children and Morgana turning evil, yet he had a sorcerer as a friend (Gaius) and spared the one who killed Igraine (Nimueh).

Anyway, considering this, I cant see him killing Vivienne. She was not only his brief affair but also the wife of his best friend and the mother of his daughter. He was always protective of those close to him and I still don't think that he didn't send the reinforces to Gorlois in order to abandon him. He seemed to be genuinely shocked when Morgana pretended to blame him about that. Nevertheless, I'm pretty sure that Vivienne is dead and that Morgana barely knew her.

@ReganX, very interesting. I don't believe they had intended to make Uther Morgana's father from the beginning. When Uther threatened Morgana, I had the impression that he wanted to scare her and that he again acted according to his short temper. When I saw it the first time back in 2008 I didn't think that he really meant what he told her.

As for worrying about not having children, it's quite possible that they tried for several years and that the affair with Vivienne happened somewhere along the way. However, given that Gaius was  very advanced in his knowledge for a physician of the dark ages, some physician, if not Gaius, may have figured that Igraine could not conceive due to other reasons, maybe a sickness or an injury or whatever. So maybe they relied on that diagnosis and it didn't took them several years trying but only one or two years. Remember, Gaius even diagnosed a bone sickness on Katrina. And for some reason he knew that a piece of the blade travelled towards Arthurs heart, not to mention that he diagnosed Morgana with a scull fracture.

It was said that Morgana is older than Arthur, but even if, your theory had ocurred to me too. Since the Triple Goddess presides and sees and knows all and actually was responsible for everything, it's not unlikely that they brought Uther into this situation in advance in order to give him a daughter with magic. I've also thought about the fact that Vivienne, as a sorceress, maybe enchanted Uther. She wasn't quite a faithful wife. She had Morgause with another man, Morgana with Uther and was married to Gorlois, so she was with three different men at least. I don't think that Vivienne was such an innocent person. Maybe she was a seer too and knew what was going to happen, hence having a child with magic close to Camelot in order to infiltrate the kingdom and to later fight Uther.

We will never know. There were so many great possibilities that the show runners could have dealt with.