User blog comment:GianG/Merlin characters ages/@comment-5674726-20141103011022

"Ginevra "Gwen": We know that Gwen is younger than Morgana and since in medieval times, men were used to marry younger women, I assumed that Gwen is slightly younger than Artù... I think that she is 19-20 in Series 1 and 26-27 in Series 5."

I would say that this logic is rather flawed. In medieval times, it would have been ludicrous for a King to marry a servant but that doesn't mean that viewers should assume that Gwen is actually a princess, so why draw conclusions about her age on that basis? The only hint we were given about Gwen's age is Elyan's comment that she raised him, which would suggest that she was the older sibling.

We have most to go on as far as Arthur's age is concerned. He turned 21 in the latter half of Season One. If each season covers a year or thereabouts then, taking the three time jumps into account, he was about 30 at the time of his death.

We have fairly substantial information to go on for Merlin's age. In the first episode, the 20th anniversary of the Great Dragon's capture is celebrated. We know that Balinor fled immediately after that and that he sought refuge in Ealdor. He does not appear to have been there long before he was tracked down and fled. From this, we may reasonably extrapolate that Merlin is 18-19 in the pilot.

We have no canonical evidence to go on for Morgana's age.

Same goes for Morgause, except that she is old enough for Arthur to find it believable that she knew Ygraine.

For Gaius, the book from Alice suggests his age in Season Three, and the series finale took place approximately six years later.

Based on Uther's remark to Arthur, he was in his early twenties when he became King of Camelot. He also won four consecutive decennial tournaments so he was old enough to fight in one thirty years prior to Season Three. Allowing for him to be married to Ygraine for at least a few years before seeking magical help to have a child by her - something I can't see him doing lightly - he was in his late forties in Season One.