In which Sherlock Holmes short story was Irene Adler featured?

Irene Adler is a fictional character in the Sherlock Holmes stories written by Sir Arthur Conan Doyle. She was featured in the short story "A Scandal in Bohemia", published in July 1891. She is one of the most notable female characters in the Sherlock Holmes series, despite appearing in only one story. In derivative works, she is frequently used as a romantic interest for Holmes, a departure from Doyle's novels, in which he harbors a platonic admiration for her wit and cunning.

According to "A Scandal in Bohemia", Adler was born in New Jersey in 1858. She had a career in opera as a contralto, performing at La Scala in Milan, Italy, and a term as prima donna in the Imperial Opera of Warsaw, Poland, indicating that she was a talented singer. It was there that she became the lover of Wilhelm Gottsreich Sigismond von Ormstein, Grand Duke of Cassel-Felstein and King of Bohemia (then only the Crown Prince), who was staying in Warsaw for a period. The King describes her as "a well-known adventuress" (a term widely used at the time in ambiguous association with "courtesan") and also says that she had "the face of the most beautiful of women and the mind of the most resolute of men". She also claims to have been trained as an actress and "often" disguised herself as a man to "take advantage of the freedom which it gives". The King eventually returned to his court in Prague, while Adler, then in her late twenties, retired from the opera stage and moved to London.