In 1875, he was appointed to the Bibliothèque Mazarine, where he was specially engaged in the compilation of an analytical catalogue from the year 1874. Meanwhile, Cahun had begun to publish a series of historical novels dealing with ancient history, in the style of the journeys of Anacharsis in Greece. They are said by one critic to be written in temperate and pure French, combining interest with genuine archeological knowledge. It was Cahun's intention to present facts of ancient history that were not generally known, and thus make contributions to general history and geography. These novels include: "Les Aventures du Capitaine Magon", on Phoenician explorations one thousand years before the common era (Paris, Hachette, 1875); "La Bannière Bleue", the adventures of a Muslim, a Christian, and a pagan at the time of the Crusades and the Mongolian conquest (ib. 1876); "Les Pilotes d'Ango", dealing with French history in the sixteenth century (ib. 1878); "Les Mercenaires", set during the Punic Wars (ib. 1881); "Les Rois de Mer", on the Norman invasions (Chasavay, 1887); "Hassan le Janissaire", on Turkish military life in the sixteenth century (crowned by the French Academy); "La Tueuse", scenes from the Mongol invasion of Hungary in the thirteenth century (1893). Cahun contributed many literary articles to the "Revue Bleue", "Le Journal des Débats", etc., and several critical, geographical, and ethnographical papers to the "Bulletin de la Société d'Ethnographie", "Bulletin de la Société Académique Indo-Chinoise" "Bulletin de la Société Japonaise", "Bulletin de la Société Americaine", "Bulletin de l'Athénée Oriental", etc.