Colin Morgan: (on Merlin) I think when we started, I knew as much about the legend as anybody. The basic sword-and-stone story, stuff like that, and of course everyone has this image of Merlin being this old guy with a beard! I've since been reading up quite a lot on Arthurian legend and there's quite a big gap missing in Merlin's life, the time when he was growing up. Why wasn't that documented? This show explores one possibility.