Watson points out that "cock fighting is illegal, and has been for fifty years." This refers to the Cruelty to Animals Act, 1835, and allows the events depicted to be dated to approximately 1885.
As the Duke gives a check to Mr. Holmes, the date on the check shows the year 1889.
The original story ended simply with the Duke telling the entire story to Holmes with the promise that Wilder would go and seek his fortune in Australia.
Holmes tells Dr Huxtable that he and Dr Watson are too busy to assist him, saying they have been "retained in this case of the Ferrers Documents, and the Abergavenny murder is coming up for trial. Only a very important issue could call me from London at present." Both cases are considered untold stories in the Sherlock Holmes canon.
Alan Howard (The Duke of Holdernesse) was the cousin of Ronald Howard, who played Holmes in Sherlock Holmes (1954).