In the Sherlock Holmes story “The Adventure of the Six Napoleons,” what object is the criminal searching for?

In “The Adventure of the Six Napoleons,” the criminal is searching for the Black Pearl of the Borgias.

The story was first published in 1904 and collected in The Return of Sherlock Holmes. Inspector Lestrade reports a bizarre series of attacks in which plaster busts of Napoleon are smashed. Holmes initially treats the pattern as deliberate rather than as simple vandalism.

The explanation is that a valuable black pearl, stolen by the criminal Beppo, was hidden inside one of the busts while he was being pursued. The busts were made from the same mould, so the criminal tried to destroy them one by one to find the hiding place. Holmes traces the final bust to the home of Horace Harker and then identifies the target of the search.

The title’s “six Napoleons” refers to the plaster busts, not to six historical portraits of Napoleon Bonaparte. The case is also known as “The Six Napoleons” in some references. The Black Pearl of the Borgias is a fictional jewel created for the story.