Prince Pierre , Duke of Penthièvre Pierre Philippe Jean Marie d ' Orléans ( November 4 , 1845 — July 17 , 1919 ) was Duke of Penthièvre and a grandson of French king Louis Philippe I . He was an officer in the Union Navy and the French Navy as well as an avid traveler . Family . Prince Pierre d ' Orléans was the son of François d ' Orléans , Prince of Joinville , and his wife Princess Francisca of Brazil . By his father , he was the grandson of the French King Louis Philippe I . By his mother , he was also the grandson of Pedro I & IV , Emperor of Brazil and King of Portugal and the Algarves , after whom he was named . Princess Françoise of Orléans ( 14 August 1844 – 28 October 1925 ) , the older sister of Prince Pierre d ' Orléans , is an ancestor of the three Orléanist pretenders to the throne of France since 1926 : Jean III ( her son ) , Henri VI , and Henri VII . Pierre d ' Orléans also had a younger sister who was stillborn ( 30 October 1849 ) . Although he never married , Prince Pierre d ' Orléans had two illegitimate children with Angélique Marie Augustine Lebesgue ( d . 1881 ) , a married woman : Life . From France to exile . Born in the Château de Saint - Cloud in 1845 , Prince Pierre was expelled from France with his family when the Revolution broke out in 1848 , which overthrew his grandfather , King Louis Philippe I . Prince Pierre had a happy childhood as a refugee in England , with the majority of the other members of the House of Orléans , despite the uncertainty of his condition as an exile . The education of Prince Pierre , along with that of his sister and cousins , was overseen by his father in England . Their education was at first organized by a tutor . In 1859 , Prince Pierre and his cousin , Prince Ferdinand , Duke of Alençon , left for Scotland to pursue further studies at the prestigious Royal High School in Edinburgh . Brazilian marriage proposal . At the beginning of 1860s , Pedro II , the Emperor of Brazil , sought to marry his daughters , Princesses Isabella and Leopoldina , to ensure his succession . Turning his gaze to his European relatives , the Brazilian emperor asked his sister , Princess Francisca , and her spouse to give him advice on two young princes who could marry his daughters . The Joinvilles gave their best advice and , among all the names they proposed to the Emperor , he selected the Prince Pierre and Prince Philippe , Count of Flanders as potential husbands for his daughters . For the Emperor , the two young men indeed offered the benefit of belonging , respectively , to the French and Belgian royal families , each a dynasty with a liberal reputation . Further , Prince Pierre had the advantage of being a nephew of Pedro II . His mother was the Emperor ' s elder sister and , through her , Pierre had his own links to the Brazilian Imperial Crown . Prince Pierre , however , wanted a career in the Navy more than anything , and thus declined his uncle ' s offer to marry Brazilian royalty . As for the Belgian Prince Philippe , he refused to leave Europe to settle in the Americas . In the end , Emperor Pedro II chose Prince Gaston d ' Orléans and Prince Ludwig August of Saxe - Coburg and Gotha as his future sons - in - law . In the United States . Desiring to follow the successful navy career of his father ( who would retire as a vice - admiral ) , Prince Pierre expressed his wish to serve on the seas to his family . Despite his young age — he was only sixteen at the time — his father , the Prince de Joinville , began looking for a military academy that was willing to receive Prince Pierre as a cadet . Eventually , thanks to the intervention of U . S . President James Buchanan , Prince Pierre gained admission to study at the United States Naval Academy in Annapolis , Maryland . Arriving in the United States with his father and two cousins , Prince Philippe , Count of Paris , and his younger brother Prince Robert , Duke of Chartres , Prince Pierre began his studies at the Naval Academy on 15 October 1861 . The Count of Paris and the Duke of Chartres were both appointed assistant adjutant general and served in the Union Navy during the American Civil War . Because Annapolis was close to the front lines of the Civil War , Prince Pierre completed his studies at the Naval Academy ' s relocated facilities at Fort Adams and later the Atlantic House Hotel , both in Newport , Rhode Island . After graduating , Prince Pierre served on the corvette , which had been a training ship for midshipmen in Newport ; he joined its crew while it was part of the South Atlantic Blockading Squadron and was stationed off Morris Island inside Charleston Bar . Unlike his father and his cousins , who left America on 7 July 1862 , Prince Pierre would stay in the United States until 1864 . He reached the rank of lieutenant on the " John Adams " . He would later resign his commission with regret , as Franco - American relations cooled with the French intervention in Mexico on the side of the Second Mexican Empire . Illness and consequences . Before resigning from the U . S . Navy , Prince Pierre sailed with the " John Adams " to the Gulf of Mexico , where he contracted malaria . He was severely affected by the disease and was treated with heavy doses of quinine , which finally cured him but caused irreversible deafness . Prince Pierre ' s deafness caused him increasing depression . Having returned to Europe , he confined himself to his studies , which would become his true passion . He thus become interested in chemistry , botany , astronomy and mechanical engineering . Travels . Since the doors of France remained closed to the Orléans family due to the post - revolution Exile Law of 28 May 1848 , Prince Pierre obtained permission , with the aid of his father , to embark for two years on the " Bartolomeu Dias " , a Portuguese naval ship on a mission in the Pacific . Aboard the " Bartolomeu Dias " , Prince Pierre served as an officer of the watch . Thereafter , Prince Pierre continued his travels around the globe . With his relative and childhood friend , Count Ludovic de Beauvoir , and Albert - Auguste Fauvel , Prince Pierre embarked on a merchant ship for a tour around the Pacific , lasting from 1865 to 1867 . The companions traveled to Australia , Java , Siam , China , Japan and California together . Fauvel and de Beauvoir would each subsequently publish several books about their travels . Afterward , he would complete other voyages elsewhere in the world . Return to France . With the fall of the Second French Empire on 4 September 1870 , Prince Pierre was finally able to return to France and become part of its Navy , which was marginally active during the Franco - Prussian War , which was essentially fought on land . Upon his entry into service for France , he was appointed lieutenant aboard the newly built ( 1870 ) frigate " L ' Océan " , under the command of Admiral Renault . On a personal level , Prince Pierre began a romantic relationship with a young married woman by the name of Angelica Lebesgue . He would father two children with her , named Jeanne and Pierre Lebesgue . Prince Pierre would raise young Jeanne and Pierre in his successive residences on " Avenue d ' Antin " ( today , " Avenue Franklin - D . - Roosevelt " ) and " Boulevard Haussmann " in Paris . Despite the scandal caused by his relationship with Angelica Lebesgue , Prince Pierre remained close to his family and regularly visited the home of his sister , Princess Françoise . Becoming fond of hunting , Prince Pierre also frequented the forest of Arc - en - Barrois , a wilderness area in the Chaumont Arrondissement containing a large game population , that he and his extended family owned . Later life . In 1883 , a new French law concerning the princes of former ruling houses obligated Prince Pierre to permanently leave the Navy . Despite the ingratitude of his country , Prince Pierre offered his château at Arc - en - Barrois , which he inherited upon his father ' s death in 1900 , to the French army during World War I . The Château d ' Arc - en - Barrois was used as a military hospital for wounded soldiers , especially from the Verdun and Argonne campaigns . Prince Pierre died a bachelor in 1919 and , having no direct heirs , passed the Château d ' Arc - en - Barrois to his nephew , Prince Jean , Duke of Guise ( Jean III , the titular king of France ) . He is buried in the Royal Chapel of Dreux , in France .