The Sign of the Four (sometimes entitled The Sign of Four) was conceived in August 1889 in the dining room of the Langham Hotel in London, at a dinner to which Joseph Marshall Stoddart, managing editor of Lippincott's Magazine, had invited the 30-year-old Arthur Conan Doyle and the already famous Oscar Wilde. Stoddart was on the lookout for short fiction, and commissioned Wilde to write the tale that became The Picture of Dorian Gray. Conan Doyle offered a second adventure featuring Sherlock Holmes and Dr Watson, who had made their debut in A Study in Scarlet, published by Ward, Lock in 1888. He seems to have finished the new story in a month, and The Sign of the Four first a…
Kerr, Douglas. "The Sign of the Four". The Literary Encyclopedia. First published 09 September 2009; last revised 30 November -1.
[http://www.litencyc.com/php/sworks.php?rec=true&UID=26982, accessed 28 April 2015.]