User blog comment:OneofthePendragon94/The age of Merlin, Arthur, Morgana and Gwen./@comment-4190137-20121115055714

More evidence shows that Morgana is older than Arthur. Because why would Uther was to have a child with another woman after the other one died the first time? And all of this couldn't have happened during the Great Purge.

Anyway let's calculate Arthur's age first. The Great Purge ended 20 years before Series 1 meaning that it would have started one or two years before. That would make Arthur 21-22 as of Series 1. And there has been eight years between Series 1 and 5 so that would mean at the start of Series 5 Arthur would have been 29-30, and let's assume at least 6-9 months have passed from Arthur's Bane: Part One and the end of The Dark Tower, that would make Arthur currently 30.

Merlin would have been about 17-18 (John Hurt used the term 'young boy' - even in Series 3) at the start of Series 1. So now Merlin will probably be around 27.

And judging by Merlin's age in Series 1, I don't think Guinevere would have been far older. And I think she would be slightly younger than Arthur. I'm not so sure about Elyan if whether she's the older, younger is twin sister to him. And since she was a 'young' maid to Morgana in Series 1, it would probably have to mean she's younger than her. This is just a guess based on little evidence, I think Gwen is 29 currently.

Morgana, now, I said earlier that I think she is older than Arthur. But not much older... And since Morgana 'beat' Arthur in sword fights as a child I doubt any younger sibling would be able to do that. I think Morgana at the start of Series 5 was 31-32 but now as it is the middle of the Series, I am going to go with 31 or if not 32. And like Nimueh did, Morgana would have the ability to make herself look younger in appearance.

Gaius, I think was 75 in Series 1 so now I think he's be 84. I think there is definitely a conspiracy behind why he's still on the show... Because no one in the middle ages made it past their late-fifties.

As for Mordred, I think he was about 9-10 in Series 1, 11 years old in The Nightmare Begins, just about 12 in The Witch's Quickening (guesses based on appearance). 20-21 in Arthur's Bane: Part One, so now he'd be 21.