The programme starred Colin Morgan, Bradley James, Katie McGrath, Angel Coulby, Richard Wilson, Anthony Head, and John Hurt.

Merlin (Colin Morgan) is a young, powerful warlock who arrives in the kingdom of Camelot after his mother arranges for him to stay with the court physician, Gaius (Richard Wilson).

He discovers that the king, Uther Pendragon (Anthony Head), outlawed magic twenty years earlier in an event known as the Great Purge and imprisoned the last dragon, Kilgharrah (voice of John Hurt), in the caves beneath the castle.

The Great Dragon tells Merlin that he has an important destiny: to protect Uther's only son, Prince Arthur (Bradley James), who will return magic to Camelot and unite the land of Albion.

But when Uther's actions eventually cause his ward, Morgana (Katie McGrath), to turn against Camelot and pursue a path of evil, Merlin and Arthur must join forces with friends, old and new, to protect their home and secure their destinies.

A year before the Shine series was initiated, writer and producer Chris Chibnall had been developing a project aimed at a BBC One Sunday night slot, but this was ultimately not commissioned.

[7] The Shine version of the project was put into development in late 2006, commissioned by Controller of BBC One Peter Fincham and BBC Head of Fiction Jane Tranter, with Fincham keen on having more series on his channel which embodied "three generation TV – that's TV you can watch with your grandparents and children.

[20][21] In a later interview, the co-creators said that while there had not been serious consideration of a sixth series, there had been "advanced talks" about a trilogy of Merlin movies set within the show's original timeline that did not end up being realized, but that they remained creatively interested in the legend.

[24] In 2009 the BBC broadcast a special in which Morgan and James took a road trip through Wales looking for traces of sites related to Arthurian legend.

[27] In April 2008, United States broadcasting rights were purchased by NBC,[28] where it was shown on Sundays at 8 pm (EST), starting 21 June 2009.

[33] The distributor, FremantleMedia Enterprises, also sold broadcast rights to CTV in Canada, Network Ten in Australia and Prime in New Zealand.

[40][41][42][43] In the U.S., the show has also been available on a variety of on-demand paid and free ad-supported streaming platforms, including Pluto TV,[44] Tubi,[45] Amazon's Prime Video[46] and Britbox.

[52] A soundtrack for the first two series featuring music from selected episodes was released on the MovieScore Media record label.

[84] UK publisher Attic Brand Media launched an official magazine for the show in September 2011 featuring articles, puzzles and a comic strip written by Damian Kelleher and drawn by Lee Carey.

"[86] The wax model cost £150,000, and the entire castle experience was part of a £3 million investment by the Merlin Entertainment Group to promote the show.