Romulus's throne was built specifically so that the feet of 15-year-old Thomas Brodie-Sangster would not touch the floor when he sat in it to reinforce the perception of a small child being dwarfed by events going on about him.
Director Doug Lefler managed to get all of the family of Thomas Brodie-Sangster in this movie (uncredited). At 01:01:10 Thomas's mother Anastasia is shown hugging Kustennin, commander of the Ninth Legion, and again at 01:09:40 as Ygraine's mother. At 01:03:25 Thomas's younger sister Ava is shown as the first Celtic girl in the scene where Ambrosinus explains the heritage of Caesar's sword. At 01:10:48 in the background by Kunstennin, as the blacksmith begins stating his view of Romulus living among them, is Thomas's father Mark.
(At around 13 minutes) Ferdinand Kingsley, son of Sir Ben Kingsley, played Sir Ben Kingsley's character in flashbacks as a young man in Britannia.
(At around 37 minutes) The statue of Gaio Giulio Cesare was not the primary statue used in Tunisia. Rather, it was a special-effects statue with a large gaping hole in its back and which was intended to be rigged to blow up. When production moved from Tunisia to Slovakia, the primary statue was lost.
Shots were removed from the U.S. version of this movie so it would receive a family (PG-13) rating (At 24:14, a shot of the crow flying down, picking up Wulfila's finger, and flying out of the room, as well as a shot at 42:06 of Wulfila's face hitting an axe blade, among other shots).