Gallo-Roman temple of Izernore

The site of the temple was certainly occupied before its construction, as evidenced by the Gallic coins found, but neither the nature nor the importance of this occupation could be determined with certainty.^[9] The construction of the first temple, the exact dating of which remains uncertain, started during the Flavian dynasty in the later half of the first century CE. The architectural fragments found in the area could not be used to date its construction as there is nothing to attribute them with certainty to this first temple.^[10] Similarly, the time of the construction of the second temple is not known, and there is no archaeological evidence to establish it. However, it was constructed after the previous phase was completed towards the end of the first century CE, and extended through the second century CE.^[11][12] These dating proposals are also based, in part, on the examination of the coins found on the site.^[13] This dating method has its limits, as imperial coins continued to circulate well after the reign of the person they commemorated and there is no evidence that the temple was still in use as a cultural monument at the time of their deposition.^[14]

The temple, like the whole ancient settlement, seems to have been abandoned at the end of antiquity or at the beginning of the Middle Ages.^[4] It is explained by the recovery of materials from the original temple which were reused in later constructions. A column of the temple forms the base of another ancient monument in the city.^[15] The site of Izernore was considered as a hypothetical location for the Battle of Alesia in the ninth and tenth centuries, based on an interpretation of Julius Caesar 's accounts.^[16] A passage from the Life of the Fathers of the Jura mentions the presence of this monument, then ruined.^[17] It was only much later that the visible remains of the temple were described by local scholars such as Samuel Guichenon (History of Bresse and Bugey, 1650), François Henry Egenod (correspondence, 1706), and Eugène de Veyle (Explanation of the Roman antiquities of Bresse, Bugey, Valromey and Gex, manuscript, 1720).^[18]

The first excavations on the site of Izernore was carried out by Thomas Riboud in 1783.^[19] The results of these excavations, taken up and synthesized by Jules Baux in 1866, consists of a description of the remains and decorations unearthed from the site.^[20] The site was classified as a historic monument in 1840.^[21] In 1863, the excavations resumed, and a detailed report was published in 1866.^[22] The site's protective fence was built in 1910, and the remains were extensively restored with the reconstruction of the base of the cella and the walls of the peristyle.^[23][15] Further research on the building was subsequently carried out under the direction of Raymond Chevallier, with the help of the Archaeological Group of the Touring Club of France, and published in an article entitled "Five years of archaeological research in Izernore" in 1968.^[24]

A project to enhance the temple was launched in the early 2010s. Following specific investigations on the site, an in-depth study of the architectural elements scattered around the monument and the nearby town and extensive documentation was carried out.^[15]

The religious function of the first monument could not be formally attested.^[25] Measuring at least 15 m (49 ft) by 17.5 m (57 ft),^[26] it appears to have the form of a single storey building, surrounded by a peripheral columns of the Corinthian order.^[27] The foundations which are approximately 0.95 m (3 ft 1 in) wide, and a few elements remain in place.^[28] The old descriptions refer to walls, partitions or cellars.^[29] The temple has an entrance on its southern side, which led to the sanctuary itself.^[30] The elements found in place, those used in the second monument and those identified nearby as possibly belonging to this temple, suggest a construction using soft limestone.^[25]

The construction of the second temple on the site of the first building and reusing some of the elements, started later. The second temple might have served for ritual functions or housed a relic earlier housed in the first building.^[31] The second building, the remains of which are still visible, is built on the foundations of the first.^[32] The walls of the first temple were surrounded externally by those of the second and only seem to be dismantled once construction was completed. This process perhaps allowed the religious functions of the monument to be maintained throughout this construction phase.^[27]

• Baux, Jules (1866). Ruines d'Izernore. Rapport à M. Léon de Saint-Fulgent, préfet de l'Ain, sur une fouille opérée en 1863 par les soins d'une commission départementale [Ruins of Izernore. Report to Mr. Léon de Saint-Fulgent, prefect of Ain, on a excavation operated in 1863 by the care of a departmental commission] (in French). Impr. de F. Dufour.
• Boislève, Julien (February 2015). "Les décors peints du temple d'Izernore" [The painted sets of the Izernore temple]. Archéologia (in French) (529): 54–55. ISSN 0570-6270.
• Buisson, André (1990). L'Ain. Carte archéologique de la Gaule (in French). Paris: Les éditions de la MSH. p. 192. ISBN 978-2-8775-4010-0.
• Chanel, Emile (1911). Catalogue of Musée archéologique d'Izernore (Ain) (in French). Courrier de l'Ain.
• Fauduet, Isabelle (1993). Les temples de tradition celtique en Gaule romaine [The temples of Celtic tradition in Roman Gaul] (in French). Errance. ISBN 2-8777-2074-8.
• Fellague, Djamilla; Ferber, Emmanuel; Parent, Daniel (February 2015). "Izernore, retour au temple" [Izernore, return to the temple]. Archéologia (529): 50–57. ISSN 0570-6270.
• Fellague, Djamilla; Ferber, Emmanuel; Parent (2017). "Le temple d'Izernore et ses pièces d'architecture". Actes du colloque international « Decorazione e architettura nel mondo romano », Rome, 2014. Quasar. pp. 189–206. ISBN 978-8-8714-0753-1.
• Saint-Didier, Balthazar-Augustin Hubert de (1837). Essai sur le Temple Antique d'Izernore en Bugey [Essay on the ancient temple of Izernore in Bugey] (in French). Imprimerie de P.-F. Bottier.
• Secondi, Claude; Donzel, Renaud (12 March 2019). D'Isarnodurum à Izernore : Un temple mystérieux [From Isarnodurum to Izernore: a mysterious temple] (in French). IDC Editions. ISBN 979-1-0943-0240-8.