Gaius: What did your mother say to you about your gifts?
Merlin: That I was special.
Gaius: You are special. The likes of which I've never seen before.
Merlin: What do you mean?
Gaius: Well... magic requires incantations, spells that take years to study. What I saw you do was... elemental. Instinctive.
Merlin: What's the point if it can't be used?
Gaius: That I do not know. You are a question that has never been posed before, Merlin.
Merlin: Did you ever study magic?
Gaius: Uther banned all such work twenty years ago.
Gaius: People used magic for the wrong ends at that time. It threw the natural order into chaos. Uther made it his mission to destroy everything from back then, even the dragons.
Merlin: What, all of them?
Gaius: There was one dragon he chose not to kill. He kept it as an example. He imprisoned it in a cave deep beneath the castle where no-one can free it.