User blog comment:Emily Windsnap/How old are the Merlin characters?/@comment-80.7.103.140-20141202010823

Merlin must be 18 in the first series because when the intro bit changes a few series later from 'young boy' to 'young man' it means he's come of age, 21. Of course series 5 had skipped three more years into the future so by the end of the show (not counting merlin as an old mam in modern day Wales), Merlin is 24-ish. Arthur is about 2-3 years older than Merlin because in the first series he is crowned prince (because that's when Kings felt 21 was an old enough age to say 'Hey, you've lived this long, well done. Now its worth giving you a title!). So by the show's end and poor Arthur dies (sorry spoiler alert, but everyone should know by now), he isn't even in the second half of the average lifespan for those days, at the age of around 27-ish :(