Ioan Gruffudd was spotted curling his eyelashes by Ray Winstone one morning before shooting. Winstone spread the word, and Gruffudd earned the nickname "Sir Lashalot" for the duration of the shoot.
The horse ridden by Bors (Ray Winstone) in the film is the same horse that was ridden by Maximus (Russell Crowe) in Gladiator (2000).
The language spoken by the Woads in the film is a combination of ancient Gaelic and ancient Welsh, as the actual language spoken by the Picts has been lost.
Although the weather seems very cold and dreary, the movie was shot during near-record high temperatures in Ireland.
Stellan Skarsgård turned the role of Cerdic down three times before director Antoine Fuqua was able to persuade him to take it. Fuqua never approached any other actor for the part.