 Complete the following phrase:  His works are numerous: Les Fées au Moyen âge and Histoire des légendes pieuses au Moyen âge; two books filled with ingenious ideas, which were published in 1843, and reprinted after the death of the author, with numerous additions under the title Croyances et légendes du Moyen âge 1896; Histoire des grands forts de la Gaule et de lancienne France 1850, a 3rd ed. revised, appeared in 1867 under the title Les Forts de la Gaule et de lancienne France; La Terre et lhomme, a general historical sketch of geology, geography and ethnology, being the introduction to the Histoire universelle, by Victor Duruy 1854; Histoire des religions de la Grèce antique, 3 vols., 18571859; La Magie et lastrologie dans lantiquité et dans le Moyen âge 1863; Histoire de lancienne Académie des sciences 1864; Histoire de lAcadémie des Inscriptions et Belles Lettres 1865; a learned paper on the reports of French archaeology, written on the occasion of the 