* ActorSharedBackground: Dimitri Leonidas is half-Greek, just like his character.
* CreatorCameo: Neil Marshall plays the archer that shoots [[spoiler: Bothos]] as he's riding towards Hadrian's Wall.[[note]]Neil Marshall would later "reprise" that part in the Game of Thrones episode "''Watcher on the Wall''", playing a member of the Night's Watch, guarding the Wall: a homage to Hadrian's Wall.[[/note]]
* TheDanza: Leonidas, played by Dimitri Leonidas.
* DatedHistory: It's a matter of some academic disagreement whether the Ninth Legion disappeared in Britannia. Neil Marshall was aware of the controversy but was more interested in telling the story of the legend than spot-on historical accuracy.
* DoingItForTheArt: Neil Marshall spent about two years working on the look of the film, adamant that it would be shot entirely on location rather than with a green screen.
* DuelingMovies: With ''Film/TheEagle'', which is based on the same legend about the Ninth Legion, though it's adapted from [[Literature/TheEagleOfTheNinth a novel]] and this isn't. In some ways ''The Eagle'' could even be seen as a sequel, as it picks up the storyline some twenty years after the Legion's disappearance.
* FakeNationality: Naturally all the actors playing the Romans - who all employ TheQueensLatin. Irish actors Michael Fassbender and Liam Cunningham and American actor JJ Feild affect English accents to play Quintus, Brick and Thax respectively.
** Ukranian actress Olga Kurylenko as Etain is a marginal example - since she's a mute who never speaks.
** The Pict leader Gorlacon is played by Danish actor Ulrich Thomsen, and his archer Aeron by Belgian actress Axelle Carolyn.
** English actress Imogen Poots is the straightest example, faking a pretty good Scottish accent as Arianne.
* WhatCouldHaveBeen: A planned subplot was to reveal that Arianne was actually Etain's half-sister - and Etain was the one who had scarred her face. Etain would have escaped the final battle, returned to Arianne's fort and been killed by her there.