Answer :
It's a work of historical fiction because it's a work of fictions set in the years of Emperor Nero. By setting his story and building his characters in a previous time period, the work is historical fiction.
Historical fiction is a genre in which the story itself is not based on true events but takes place in the past and sometimes borrows characters from history.
"The Contest" by Sir Arthur Conan Doyle is a work of historical fiction because it is set in the year 66 and follows the adventures of Emperor Nero who was the last Emperor before the Julio-Claudian dynasty.
