Rudolf, Crown Prince of Austria was the only son of Emperor Franz Joseph I of Austria and heir to the Austrio-Hungarian throne. He died in his hunting lodge at Mayerling under mysterious circumstances on January 30, 1889, where he apparently committed suicide after killing his mistress.
The suicide of the Austrian crown prince was widely reported in the newspapers, which brought it to Sherlock Holmes' attention. He linked the prince's death numerous other seemingly unrelated incidents, and realized they were connected in a massive conspiracy. He determined this plot was calculated to destabilise Europe and cause a world war as part of a war-profiteering scheme, and was masterminded by none other than his arch-nemesis, Professor James Moriarty.
- Rudolf's death was in fact highly destabilising in Europe, as it left Franz Josef without a direct male heir. The assassination of Archduke Franz Ferdinand, next in line to the throne, was what triggered World War I.
- The body of the newspaper article in Holmes' study was copied directly from Rudolf's entry on Wikipedia.
- Rudolf, Crown Prince of Austria on Wikipedia.