Trivia: Throughout the show, the number 47 appears many times. There are multiple room 47's (where Syd found the Circumference in season 1 and the room in her memories from season 3, among others.), there are 47 Rambaldi artifacts, and Page 47 of the Rambaldi manuscript was the page that had Sydney's picture on it.
Trivia: A film reference to Star Trek: First Contact: Archer says something about a group of cybernetic creatures (The Borg), that tried to stop Cochrane from launching his mission into space that was stopped by a group of humanoids, that were also from the future (USS Enterprise NCC 1701-E).
Trivia: In the scene where the Red Devils toast the 101st Airborne, when the camera shows the assembled soldiers you'll see Tom Hanks as one of the Red Devils in a beret at the back left (5 or 6 men in) with his right hand on his hip. His head moves forwards to become obscured behind another soldier. (00:30:30)
Trivia: In series 5 in the episode "Fresh Lick," when Tam shows Navid the video tape in the back of the shop, the customer gets impatient and says she is going to Kohli's. This is a mention to Navid's actor Sanjeev Kohli.
Trivia: Andrew McFarlane has played two characters on the show, who were both Claire's boyfriend. He first appeared in the season 1 episode "Breaking Up and Breaking It" as Roger, Claire's boyfriend who was more interested in playing video games with Michael than being with Claire. He then landed the recurring role of Tony, Claire's religious boyfriend. He first appeared as Tony in the season 2 episode "Letting Go".
Trivia: In the movie, a soldier called Petronius unsuccessfully tries to murder the emperor Valentinian. The name "Petronius" was probably chosen because in reality the emperor was eventually killed by a senator called Petronius.
Trivia: Nergal is the villain introduced in this episode. "Nergal" originally was the name of the Babylonian God of Fire and Guardian of the Underworld. In the Bible, he is one of the demons allied with Satan himself. In the series Nergal is associated with the underworld and fire.