Visite du temple archéologique d'Izernore

Archaeology and Gallo-Roman heritage

After starting out as a small Gaulish town, Izernore became an important vicus in the Gallo-Roman era. The remains of a temple, unique in Ain and dedicated to a still mysterious divinity, provide the only reminders of this key period of our local history.

Izernore, an old Gallo-Roman town

To this day, Isarnodurum is the only conurbation in Haut-Bugey known to date back to Antiquity. The town existed before the Roman conquest of Gaul, as evidenced by the discovery of ceramics, coins and assorted fibulae dating from the 2nd and 1st centuries B.C. Isarnodorum lay to the south of the Sequani's territory. This Gallic tribe controlled an area corresponding roughly to present-day Franche-Comté.
  • Temple Gallo Romain d'Izernore
    Temple Gallo Romain d'Izernore - ©M.Chanel_HautBugeyTourisme

After the Roman conquest, the site developed and became a vicus (a rural town of medium size and importance). The remains of the temple are the last reminders of this period still standing. Yet archaeological excavations have identified other Gallo-Roman constructions that are nowadays invisible, like the thermal baths. This relatively large building was made up of a dozen rooms. Hot and warm rooms, heated by a hypocaust (floor heating system), along with a large pool, provided a place to wash and relax, Roman-style.

did you know ?

In the 19th and early 20th centuries, several authors tried to prove that Izernore was once Alesia, where the Battle of the Gauls took place.

Houses and shops on either side of a road formed the heart of the vicus. Their excavations demonstrated that trade and craft activities took place in this complex. There is proof of agricultural activities outside of the vicus, in the hamlets of Bussy and Pérignat. The villa discovered in Pérignat in the early 20th century shows the high standards of living enjoyed by its owners. Its residential part was decorated with murals painted using techniques imported from the Italian peninsula. Upstairs, a gallery supported by columns overlooked the villa’s courtyard and offered a direct view of the Oignin Valley.

  • Visite Musée Archéologique d'Izernore
    Visite Musée Archéologique d'Izernore

Le temple, un vestige antique unique

The only example of Gallo-Roman architecture still standing, the temple of Izernore is one of the most remarkable ancient sites in the region. Its three corner pillars, now standing 9 m high, have attracted the interest of historians, archeologists, scholars and other enquiring minds since the mid-17th century. The excavations revealed the existence of two successive edifices in the same place. The ruins visible today belong to the second state of the temple, built in large stonework in the end of the 1st and the 2nd centuries. This imposing edifice rested on a podium of 2.80 m.

Reconstruction of the temple of Izernore

  • Monumental staircase: 22.60 x 19.20 m
  • The cella: 12.80 x 7.80 m
  • The podium: 2.80 m
  • Pillar height: 6.30 m
  • Estimated number of columns: 26
    (4 pillars with engaged columns)

It was accessed by a grand staircase that ran along the east façade. A colonnade stood on all four sides of the building. In the centre, you can still make out the foundations of the cella, the room reserved for the statue of the divinity. The fragments of mural paintings and decorative elements carved into the limestone or marble, unearthed on the site, allow us to form an idea of the temple’s rich ornamentation.

Despite the many archaeological excavations that have taken place there since the late 18th century, the monument has not yet revealed all its secrets. Many questions remain unanswered to this day, starting with the identity of the god who was honoured there. An inscription to Mercury, of uncertain provenance, suggests that the sanctuary was dedicated to him. A dedication to Mars, found re-used in a building in a neighbouring municipality, and a path near the temple being called “vi de mars”, have led people to believe that it was a monument offered to the god of war.

did you know ?

The remains of the temple are part of the first list, drawn up in 1840, of France’s protected historic monuments (just 4 in the department of Ain).

  • Visite du temple Gallo Romain d'Izernore
    Visite du temple Gallo Romain d'Izernore - ©Roger Gros
  • Visite du temple Gallo Romain d'Izernore
    Visite du temple Gallo Romain d'Izernore - ©Roger Gros


Some Gallo-Roman remains have been unearthed a few kilometres from Izernore, in the municipality of Montréal-La-Cluse. Part of the site was excavated in the early 20th century, and the search was resumed over a larger area in 1996. It led to the discovery of a vast complex of homes, occupied and remodelled between the 1st and 4th centuries. Are they the remains of a vicus (named Orindis in the local tradition) or of a large villa, the centre of a farm whose buildings performed agricultural and residential functions ?                                                                    The latter theory seems the most likely.


 The stones tell you their story

In the middle of the village, set off to explore Izernore, from the Isarnodurum Archaeological Museum to the ruins of the ancient temple. Follow the Path of the Stones (Chemin des Pierres) to be immersed in the past and present life of Izernore.

  • Musée Archéologique d'Izernore
    Musée Archéologique d'Izernore

Free trail outside. 7 explanatory signs with humorous illustrations are arranged along this themed trail. The “Path of the Stones” invites everyone to learn about the history and development of Izernore through the various types of stone in the village:

– sacred stone (the church and saints of Izernore, “Fathers of Jura”, founders of the Abbey of Condat – Saint-Claude)
– re-used stone (the cross on the square)
– wet stone (washhouse)
– cut stone (equestrian centre)
– renovated stone (farms of Bugey and economic life)
– planted/burnt stone (Resistance during the Second World War)
– ruined stone (the Gallo-Roman temple)


The name Isarnodurum is thought to come from the Celtic “isarno” (iron) and “duro” (market).


Musée archéologique d’Izernore
Place de l’Eglise – 01580 Izernore
Tél. + 33 (0)4 74 49 20 42

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