When Tom asks minister Chamberlain (a real historical figure) how Violet manage to invite him, Chamberlain mentions his brother-in-law Horace De Vere and Tom recalls a prank on a warship. The incident, "The Dreadnought Hoax", really happened in 1910 when De Vere and his circle of friends (including Virginia Woolf) boarded the Royal Navy's flagship HMS Dreadnought dressed as Abyssinian royals and demanded to see the ship. They received the treatment of a state visit, complete with a parade (where the wrong anthem was played) and a formal photograph, always speaking among themselves in a made-up language while De Vere "translated". On having any particular part of the ship pointed out the fake delegation would exclaim "bunga, bunga!" in admiration. The visit was cut short when a light drizzle threatened the makeup of the pranksters, but they disembarked without being discovered. As expected, the Royal Navy was a laughingstock for several months, and the admiral and officers involved had to endure yells of "bunga, bunga" wherever they went. While De Vere and his friends were summoned for punishment, there was none in the end. The prank was remembered, nevertheless, as during WW1 HMS Dreadnought managed to sink a German submarine and, reportedly, among the congratulatory telegrams, one arrived bearing the message "BUNGA, BUNGA".
Henry Talbot refers to Mary as "La belle dame sans merci," which is a reference to a poem of the same name by John Keats.
The episode won an Emmy Award for Outstanding Production Design for a Narrative Period Program (One Hour or More).
When Minister of Health Neville Chamberlain visits Downton Abbey, it is rumored that he could become Prime Minister one day. The real Chamberlain would indeed become Prime Minister in 1937, but his inability to stand up to the rising power of Nazi Germany forced him to resign in 1939, soon after the start of the Second World War which he had desperately tried to prevent.
When Violet says "When we unleash the dogs of war we must go where they take us", she is making reference to Shakespeare's "Julius Caesar" in which Mark Antony says "Cry havoc! And let slip the dogs of war."