Roots: McIntee references Lacroix's Of the Middle Ages as a source material. The novel opens with quotations from Shakespeare's Hamlet and Troilus and Cressida. The introduction gets the inevitable "Spanish Inquisition" joke from Monty Python's Flying Circus out of the way. There are references to The Lord of the Rings, Doug McClure, Montezuma, the Marie Celeste, Conan the Barbarian, Boudicca, Gwen Avur, Robin Hood, Star Wars (Obi-Wan Kenobi), Tomas de Torquemada, the Marquis de Sade, Cluedo, the I Ching, Aristotle, Homer's The Odyssey and The Iliad, Auschwitz, and Shakespeare's Henry V. The Doctor misquotes Macbeth. The Doctor's everlasting matches first appeared in David Whitaker's Doctor Who in an Exciting Adventure with the Daleks. Star Trek (class M planets, and the card game the Doctor and Benny play is "Fizbin" invented by Kirk in the Star Trek episode "A Piece of the Action").
Goofs: The Doctor notes that he once intended to visit Blackpool, but never quite made it (Revelation of the Daleks), which flatly contradicts The Nightmare Fair. [Perhaps he's referring to unrecorded events instead.]
Dialogue Disasters: "You worthless afterbirth of a rutting donkey!"
Dialogue Triumphs: "He will do what he feel is right, I imagine. That is the only certainty."
"Can you imagine the Hundred Years War with rocketry?"
"It'd probably be a lot shorter."
Guy compares the Doctor to an owl; when Bernice asks him if he means that he is wise, Guy responds, "What has wisdom to do with owls? He is comfortable in the darkness, as they are, and I think he is equally as adept at hunting down prey in cold blood."
Continuity: The Doctor poses as Jean Forgeron de Gallifrey, Royal Observer from the court of Alexander; he carries a writ of safe convoy signed by John Baliol and Alexander II. He later uses the alias Quiquaequod (The Daemons). He renders a man unconscious with a slight pressure to the neck. He plants a tracking device on an escaped prisoner, which he can follow using his telescopic probe. He's mistaken for a Scotsman, due to his accent. He and Bernice both don chain-mail armour in Medieval France.
Bernice knows aikido, but is rather rusty at it. She falls in love here with Guy de Carnac, whom she last sees fighting out-numbered in order to allow her and the Doctor to escape; she never finds out whether he lives or dies. She used to sneak off to a Tri-V museum instead of attending astrophysics classes. She has a beer glass from Callahan's. The Doctor inoculates her against the plague. She carries a slim leather pouch containing metal scrapers, which she uses for scraping rock from small fossils. She dons a thin insulating suit that she finds in a drawer in the Jade Pagoda and later wears a leather jerkin at the Roc. She has visited Nekros (Revelation of the Daleks). She speaks Ancient Tzun (First Frontier) as does the Doctor. She has a nightmare in which she is hunted down by Daleks. She knows basic first aid, including CMR. She carries a torch in Medieval France. She builds a still to distil alcohol, ostensibly for medical reasons, but which she uses to make vodka. She spent the early years of her life on Vandor Prime in Gamma Delphinus IV, which has two suns and no snow. It is implied that she watched Star Wars whilst in Oxford (The Dimension Riders).
As well as the Cloister Bell, the TARDIS has a life-support failure alarm, and a high-pitched structural integrity alarm. All three consoles have direct access to the ship's real-world interface. The TARDIS has wood paneled corridors and a thirties-style cage lift, an arboretum, a hospital ward (The Invasion of Time), a complete indoor sports centre, a tennis court, a groundcar garage, a water purification plant, and a quarantine bay. It contains a "Wanted" poster of Doc Holliday (The Gunfighters), a Veltrochni tree sculpture (First Frontier, The Dark Path), a Greek statuette of the goddess Athena, a small statue of Atlas holding the world, an Inca quipa, and the arms of the Venus de Milo. The TARDIS passes too close to a black star, causing a relative time displacement wavefront to pass through it; it isn't a threat to the TARDIS, but would kill the occupants, forcing the Doctor and Bernice to evacuate in the Jade Pagoda (Iceberg). The Doctor takes some medical supplies from the TARDIS infirmary, including broad-spectrum antibiotics, and a few immunizations with a hypospray. A draw in a stack of drawers in the Jade Pagoda contains thermal blankets, emergency rations, torches, everlasting matches, a Swiss Army knife, a brandy hip-flask, and half a dozen paperback books including Junior Colour Encyclopaedia of Space, a book on mythology by Gilbert Horner, a Charles Fort collection, and an Agatha Christie novel with the last couple of pages ripped out.
Guy de Carnac's sword was forged of Damascus steel by a smith called Wayland who claimed to know the secret of forging magical weapons from before Atlantis fell (The Time Monster). Spacefleet veterans who knew her know unrequited love as "Ace's Kiss of Death".
Sir Gilles Estram was apparently a real knight, murdered by the Master before he impersonated him (The King's Demons). A noblewoman who admired Homer's earlier work wrote The Odyssey [and is possibly meant to be Vicki (The Myth Makers)]. Arthur Pendragon's crown and a fake Christ's skull, as well as the original manuscript of The Odyssey and texts by Albucasis and St. Antony are hidden in the secret library in the Roc.
Links: The Cloister Bell was first mentioned in Logopolis. The Doctor notes that he was at Fitzwilliam Castle on the eve of the signing of the Magna Carta (The King's Demons). The TARDIS has only just left Gadrell Major (Infinite Requiem). There are several references to Ace's departure (Set Piece). The tertiary console room first appeared in Nightshade. The Doctor notes that he has occasionally had to jettison parts of the old TARDIS (Logopolis, Castrovalva), whereas his current one is complete (Blood Heat). He mentions his restaurant, Tempus Fugit (The Crystal Bucephalus). There are references to the Monk and Artemis (No Future), the Guardians (The Ribos Operation), the Old Ones and Ry'leh (All-Consuming Fire), Haiti (White Darkness), the Master (First Frontier), Vampires (Blood Harvest), Chronovores (No Future), "fossilized amoebas the size of planets" (Parasite), Chelonians (The Highest Science), the Doctor's speakeasy in Chicago (Blood Harvest), Davros, and Centaurans (The Curse of Peladon, The Monster of Peladon, Legacy).
Location: The Roc of the Cathares, France, 1242.
Unrecorded Adventures: The Doctor has been stranded on the glaciers of polar Mars, and has visited the jungles of Veltroch (see Mission: Impractical), the plains of Leng, and the fire sands of Canopus III. He owns a hip flask of brandy belonging to Napoleon. It is implied that the Doctor has met Alexander II.
Q.v. Benny's Birthday, Love and War.
The Bottom Line: 'We have to get back. I can't let him die!' The first pure historical Doctor Who story since Black Orchid is a gripping thriller, combining a whodunnit murder mystery, political intrigue, and some thoroughly despicable villains. But it is Guy de Carnac, and Bernice's doomed romance with him, that steals the novel, making Sanctuary a highlight of the range.