The brief appearance of Simon Callow as Charles Dickens marks the first time that any character (other than the Doctor or River Song) from series 1-4 has appeared on-screen in an eleventh Doctor story. Callow previously played Dickens in the first season story "Doctor Who: The Unquiet Dead (2005)".
The Doctor learning of The Brigadier's death was a tribute to Nicholas Courtney, who passed away the same year. The episode also contains scenes in which "everybody was wearing an eyepatch", a reference to the alternate universe Brigadier in "Inferno". Furthermore, Amy says to the Doctor "We'll be in Cairo soon", Cairo being Courtney's place of birth. Steven Moffat said of the reference, "In a story about the Doctor going to his death, it seemed right and proper to acknowledge one of the greatest losses Doctor Who (2005) has endured."
Brigadier Alistair Gordon Lethbridge-Stewart is said to have died in his sleep peacefully at a nursing home. In "Battlefield", The Seventh Doctor stated that this was exactly how his old friend would pass away.
The script called for an Indiana Jones style tunnel for the Headless Monks' chamber, but as that kind of location was not available in Cardiff a set was built instead.The skulls were hand-crafted and required a lot of preparation, so it was one of the first things started for the episode's production.
In post-production, one major change to the episode - which acquired the title The Wedding Of River Song - was the introduction of the "eye drive" terminology. Originally, these devices had been called "data cores", but Steven Moffat came to worry that viewers might not know that this was referring to the eyepatches.
In the back-story of Madame Kovarian (Frances Barber), the main antagonist in Series 6: she was a member of the Papal Mainframe space church, which Tasha Lem (Orla Brady) is the Mother Superior, but left the Papal Mainframe and became a servant of the Silence religious order.
The Doctor calling the retirement home and learning Brigadier Lethbridge Stewart passed away was added in the script by Steven Moffat as tribute to Nicholas Courtney whom passed away during production on Series 6 on 22nd February 2011.
The trivia item below may give away important plot points.
During the conversation between The Doctor and River where they ultimately say their vows, a theme is playing in the soundtrack that has recurred throughout this season as a theme for River. If you listen carefully, the tune repeats itself in slightly different ways, morphing into what can clearly be heard as the common bridal tune "Here Comes the Bride", revealing that the composer, Murray Gold, had this inspiration in mind the whole time. His rendition of the tune is slow and sad, however, reflecting the pain that comes along with River's love for The Doctor.