Definitions differ as to what constitutes a historical novel. On the one hand the Historical Novel Society defines the genre as works "written at least fifty years after the events described", while critic Sarah Johnson delineates such novels as "set before the middle of the last [20th] century […] in which the author is writing from research rather than personal experience." Then again Lynda Adamson, in her preface to the bibliographic reference work World Historical Fiction, states that while a "generally accepted definition" for the historical novel is a novel "about a time period at least 25 years before it was written", she also suggests that some people read novels written in the past, like those of Jane Austen (1775–1817), as if they were historical novels.
Historical fiction sometimes encouraged movements of romantic nationalism. Walter Scott's Waverley novels created interest in Scottish history and still illuminate it. A series of novels by Józef Ignacy Kraszewski on the history of Poland popularized the country's history after it had lost its independence in the Partitions of Poland. Henryk Sienkiewicz wrote several immensely popular novels set in conflicts between the Poles and predatory Teutonic Knights, rebelling Cossacks and invading Swedes. He won the 1905 Nobel Prize in literature. He also wrote the popular novel, Quo Vadis, about Nero's Rome and the early Christians, which has been adapted several times for film, in 1913, 1924, 1951, 2001 to only name the most prominent. Sigrid Undset's Kristin Lavransdatter fulfilled a similar function for Norwegian history; Undset later won a Nobel Prize for Literature (1928).
Many early historical novels played an important role in the rise of European popular interest in the history of the Middle Ages. Victor Hugo's The Hunchback of Notre Dame often receives credit for fueling the movement to preserve the Gothic architecture of France, leading to the establishment of the Monuments historiques, the French governmental authority for historic preservation. Rita Monaldi and Francesco Sorti's historical mystery saga Imprimateur Secretum Veritas Mysterium has increased interest in European history and features famous castrato opera singer Atto Melani as a detective and spy. Although the story itself is fiction, many of the persona and events are not. The book is based on research by Monaldi and Sorti, who researched information from 17th-century manuscripts and published works concerning the siege of Vienna, the plague and papacy of Pope Innocent XI.
The genre of the historical novel has also permitted some authors, such as the Polish novelist Bolesław Prus in his sole historical novel, Pharaoh, to distance themselves from their own time and place to gain perspective on society and on the human condition, or to escape the depredations of the censor.
In some historical novels, major historic events take place mostly off-stage, while the fictional characters inhabit the world where those events occur. Robert Louis Stevenson's Kidnapped recounts mostly private adventures set against the backdrop of the Jacobite troubles in Scotland. Charles Dickens's Barnaby Rudge is set amid the Gordon Riots, and A Tale of Two Cities in the French Revolution.
In some works, the accuracy of the historical elements has been questioned, as in Alexandre Dumas' Queen Margot. Postmodern novelists such as John Barth and Thomas Pynchon operate with even more freedom, mixing historical characters and settings with invented history and fantasy, as in the novels The Sot-Weed Factor and Mason & Dixon respectively. A few writers create historical fiction without fictional characters. One example is the historical mystery series Masters of Rome by Colleen McCullough.