Koenigsmark (French: Kœnigsmark) is a 1918 Ruritanian novel by Pierre Benoît.[1][2] The book - Benoît's first - was a bestseller in France; the English version, released as The Secret Spring in 1920, enjoyed only limited success.
The main narrative is told as a flashback from the front lines of World War I in October of 1914. The unnamed narrator, a young officer in the French army, is part of a trench unit commanded by Lieutenant Raoul Vignerte, with the two becoming fast friends. They learn the unit facing them is from the fictional German principality of Lautenburg-Detmold, a fact that leaves the conscientious and intelligent Vignerte visibly troubled; in the course of a sleepless night in a dugout, the narrator offers to listen if he wishes to unburden himself. Vignerte accepts, and shares an account of his experience at the archducal court of Lautenburg-Detmold just before the outbreak of the war.
In late 1913, Vignerte, nearly broke and faced with an impasse in his academic career, is contemplating giving up and accepting a dreary teaching job when he - by chance - runs into a university classmate who has risen to a position as a secretary in the foreign ministry. The friend recommends him for a position in Lautenburg-Detmold, whose Grand Duke has asked the French ambassador to procure a tutor for his fifteen-year-old son. Dazzled by the generous honorarium the position comes with, Vignerte gently dismisses the misgivings of his beloved mentor, Professor Thierry, who insinuates that there is something ominous about the archducal household, though he is not willing to give further details except to warn him to have nothing to do a baron von Boose.
Vignerte arrives at the palace and acquaints himself with its small social circle - except for the Grand Duchess Aurora, the mysterious Russian wife of Grand Duke Friedrich (and widow of the previous Grand Duke, Friedrich's brother Rudolf, who had died on a expedition to Africa shortly after marrying her.) Upon seeing the beautiful and elegant Aurora for the first time at a military parade in December, Vignerte immediately develops a powerful, irrational infatuation, but at their first meeting at a grand reception that night, Aurora mockingly dismisses Vignerte after he chivalrously attempts to return a flower she has dropped.
The lovesick Vignerte attempts to bury his frustration in work, delving into the archducal library, whose rare manuscripts he had promised to collate for Professor Thierry, a specialist in German history. The narrative veers into a lengthy digression recounting the events surrounding the mysterious 1694 disappearance of Philip Christoph von Königsmarck, a young nobleman thought to have been murdered while conducting an affair with Sophia Dorothea of Celle, the unhappily-married Electrix of Hanover. Vignerte intimates that the fate of the two lovers foreshadows events that will come to pass in the main narrative. In a different volume, he finds the handwritten itinerary of the ill-fated African expedition that took Grand Duke Rudolf's life; he sends it to the Grand Duchess, hoping that it will serve as an opening. He is rewarded with an immediate audience in which Aurora apologizes for her earlier rudeness - suggesting it was unavoidable, for reasons left unsaid - and invites him to her chambers. Aurora and her handmaiden Melusine dazzle Vignerte with exotic splendor, while her devoted equerry Hagen seethes with jealousy at his presence; from that point onward, he becomes one of the Grand Duchess' intimate companions. The Grand Duke visits during a lesson and commends Vignerte on his work with his heir; he is surprisingly unconcerned by the amount of time the tutor is spending with his wife, and thanks him for lifting her spirits.
In another, lengthier digression, Aurora shares the history of her family and her own path to Lautenburg with Vignerte in a multi-chapter-length monologue. Her family hail from Tyumen in Western Siberia and are of princely rank, tracing their descent back to a 10th-century vassal of Yaroslav of Kyiv. More recently, they have ruled a domain on the Volga not far from Astrakhan, where they have intermarried with Armenians, Kalmyks, and Persians, as well as - more recently - Western European nobility, Aurora's own mother having been a Hohenzollern princess. She describes her childhood in a palace on an island on the Volga, her love of shooting, riding, and the hunt, and - ominously - an incident in which her father brutally murdered her Italian piano teacher after he had made an advance on her. She explains that she met Grand Duke Rudolf - a quiet, awkward, sincere man - during a visit of the Kaiser to Moscow. He had immediately asked for her hand, an offer which she initially spurned, but relented to please her ambitious father and to satisfy her own bemused guilt after leading Rudolf on a hard ride during a court hunt, which resulted in his breaking his leg. In accepting his proposal, however, she had warned Rudolf that all he could expect from her was loyalty and friendship, not love; in the year after the marriage, when his secret hope that he might thaw her does not bear fruit, the Grand Duke grows melancholy and withdraws into his hobby, the study of geology. He is delighted when the Kaiser gives him a secret mission to study potential mineral deposits in a disputed part of Cameroon, and travels there with his adjutant von Boose, dying of sunstroke mid-expedition.
Aurora inherits the throne of Lautenburg-Detmold and rules alone for six months, after which she suddenly comes under intense pressure from both her father and the Kaiser to marry Rudolph's brother Friedrich. Her father's motivation is to keep her in the line of succession for the throne of Wurtenberg (which is governed by the Salic Law, and therefore closed to women.) The Kaiser's intervention in the matter is (in Aurora's opinion) due to extortion by Friedrich; she mentions the then-recent Eulenburg affair, strongly insinuating that Friedrich is homosexual and was in possession of kompromat on two imperial princes. Bowing to the inevitable, Aurora marries her former brother-in-law in March of 1912; to his polite bemusement, she orders the corridor connecting their bedrooms walled up while the wedding banquet is in progress.
In May 1914, Vignerte discovers the long-lost deathbed confession of one of the assassins of count Königsmarck in the archducal archives. It mentions a hidden chamber in which the body was first secreted; realizing that the same craftsman that had installed it in Hanover palace had also worked on the Lautenburg one, Vignerte sneaks into the armoury and find an identical hidden passage in its fireplace, accessed by a "secret spring." Behind several gates, one booby-trapped, he finds a chamber in which there is evidence of body having been dissolved in quicklime, with only bone fragments remaining. The tibia has a characteristic fracture mark; the unspoken implication is that Rudolf had never left Lautenburg, but had been murdered (at Friedrich's behest) by von Boose, who had afterward forged the Grand Duke's African correspondence.
Shaken, Vignerte informs Aurora, who - after an enormous initial shock - resolves to view the remains herself. The two are covertly making their way to the armoury near midnight when a fire suddenly erupts in the wing of the castle containing it. Vignerte runs into the burning building and discovers his bedroom has been bolted from outside, in an apparent attempt to kill him. The fire is put out, and blamed on the experiments of the young Duke's science tutor, who had operated a lab in the wing and had died in the conflagration. Aurora intimates that only one other person had known of her purpose that night; the following day, she cold-bloodedly murders Melusine in a staged hunting accident, as Vignerte watches in horror. Vignerte is himself challenged to a duel by Hagen, driven mad with jealousy, but Aurora suspects something and interrupts the duel, chastising both and ordering Hagen into house arrest.
Aurora reveals she has summoned von Boose from Africa to Lautenburg, in order to unmask the conspiracy behind her husband's death. Suddenly, events are interrupted by the outbreak of WWI; Hagen shows up to arrest Vignerte, suddenly an enemy alien, but Aurora uses her hold on Hagen to extort his cooperation and personally speeds Vignerte to the French border, where the two part. Vignerte's story ends.
The narrator is ordered to a command post to help interrogate a captured German officer, who - he realizes - is von Boose. On his person, he finds an unsent letter to Grand Duke Friedrich, confirming von Boose's complicity in the murders of the former Grand Duke and the Grand Duchess and threatening to expose Friedrich's part in the plot unless he is reassigned to a place of safety, away from the front lines. The narrator ask that Vignerte be called for, but as he approaches the post he is caught in the open during an artillery barrage and killed.
The novel has been adapted for the screen four times: a 1923 silent film was followed by (French-language) sound versions in 1935 and 1953, and a Franco-German TV movie in 1968.