Concilium totius Galliae, Lugdunum, Augusta Raurica, Aventicum and Helvetia
16 September 2026
Augustus (63 BC – 14 AD) became the new ruler of the Roman Empire in 31 BC, following a civil war (44–31 BC). However, due to Rome’s centuries-old republican past and the aversion to a monarchy, from 27 BC onwards he styled himself Princeps, first among equals or first citizen. He was no ordinary man, but the adopted son of Julius Caesar (100–44 BC). Born as Gaius Octavius, he took the name Gaius Julius Caesar following his adoption.
Reconstruction. Collection: Lugdunum-Musée et théâtres romains
The imperial cult
In reality, however, he established an autocracy or monarchy. Resistance amongst the elite of ancient Rome was considerable, however, and in the newly conquered territories too, propaganda, career opportunities, peace and prosperity were needed to justify and maintain his autocracy. One tool was the imperial cult.
The princeps, or Imperator Caesar Augustus, and his family members were accorded divine status. This status was embodied in statues placed amongst the gods, in temples dedicated to them, at religious gatherings and, above all, on one of the many religious festivals.
Rome was a thoroughly religious society. Priests or magistrates of the Ordo Decurionum (the elite body of administrators and priests) were in charge of the imperial cult at the local level. The imperial cult also served as an important tool for propaganda and self-representation in the conquered Celtic territories of what is now France and Switzerland.
Map of the Tres Gallae. Collection: Lugdunum – Museum and Roman Theatres
Lugdunum (modern-day Lyon) was, for the Celtic tribes in the provinces of Gallia Lugdunensis, Gallia Belgica and Gallia Aquitania, the venue for the annual assembly of the Concilium totius Galliae, or Concilium Galliarum, the Council of the Gallic tribes in the Tres Galliae (Julius Caesar in the *Bello Gallico*).
Delegations from 60 Gallic towns gathered at this assembly, including those from the territories of the Helvetii (with Aventicum, now Avenches, as their capital) and the Rauraci (with Augusta Raurica, now Augst/Kaiseraugst, as their capital).
Model of the Mausoleum of Lucius Munatius Plancus in Gaeta. Collection: Lugdunum-Musée et théâtres romains
Lugdunum was the provincial capital of the Provincia Gallia Lugdunensis. Gallia Narbonensis (with Genava/Geneva) was not part of this province. Lucius Munatius Plancus (87–15 BC) founded Lugdunum in 43 BC and had already founded Colonia Augusta Raurica in 44 BC. He was therefore not the founder of Basilia (Basel), a small Celtic settlement.
The assembly took place at the sanctuary of the Three Galliae on the hill of the Croix-Rousse. This Council had political and religious functions. It formed part of the imperial cult, deliberated and debated Gallic issues, corresponded with Rome (that is to say, the Senate and the Emperor), and discussed fiscal matters and numerous other issues. During this gathering, the delegates also chose a priest to lead the religious ceremony at the sanctuary.
Jean-Claude Golvin, in *L’Antiquité retrouvée*, 6th edition, Actes Sud, 2025. Reconstruction of the amphitheatre. Collection: Lugdunum-Musée et théâtres romains
Later in the 1st century, an amphitheatre was built on the site of the sanctuary, the first of the three in Gaul. As far as is known, it was also the first amphitheatre in the three Gauls and, following various extensions, had a capacity of 20,000 spectators.
An original transcription of Emperor Claudius’s speech to the Senate in 48 AD. Claudius requested that the Senate grant the highest Roman legal status to 60 Gallic cities and towns of the Concilium totius Galliae. Collection: Lugdunum-Musée et théâtres romains
The large complex comprising the amphitheatre, the sanctuary and their many statues has almost entirely disappeared. Various inscriptions, foundations and, in particular, the bronze tablet recording a speech by Emperor Claudius (10 BC – 53 AD) on the Croix-Rousse refer to this Council and its location on the Croix-Rousse.
Just as in Aventicum, Augusta Raurica and the nearby Vienna (now Vienne in the Roman province of Gallia Narbonensis), the imperial cult was also omnipresent in Lugdunum.
Reconstruction of the theatre-and-odeon complex. Collection: Lugdunum-Musée et théâtres romains
Roman theater
The Romanisation of this region, home to the Celtic tribe of the Allobroges, took place over two generations, and numerous archaeological finds – including sculptures, magnificent mosaics, a theatre, an odeon, an amphitheatre, villas, a forum, a basilica, thermal baths and other Roman structures – bear witness to this.
Furthermore, Lugdunum, together with Vienna, was an important trading centre on the Rhône (Rhodanus), with links to Genava, Augusta Raurica, Aventicum and numerous other places in present-day Switzerland.
Collection: Lugdunum-Musée et théâtres romains
Conclusion
According to some historians, the fall of the Roman Empire was due to the rise of Christianity, the enormous size of this multi-ethnic state, the degeneration of the administrative elite, or a combination of factors (economic and fiscal turmoil, administrative chaos, and civil wars or invasions by other peoples). It was probably a combination of factors, though we should not forget that the Eastern Roman Empire, or Byzantium, survived until 1453.
Collection: Lugdunum-Musée et théâtres romains
There is also another perspective. How did this vast Empire, with limited means of communication and many cultures, manage to survive for so long? One explanation lies in administrative decentralisation, the added value of the Roman quality of life, and Romanisation. The conquered territories in Western Europe were only too happy to adopt the Roman language, culture and way of life. This did not always apply to the even older cultures in Greece, parts of Turkey and the Middle East.
Collection: Lugdunum-Musée et théâtres romains
In the Roman Empire, decentralisation and relative autonomy at local level were the guiding principles. Provided that taxes were paid, no uprisings took place and the emperor was revered as a divine figure, Rome left local administrators to their own devices. Moreover, political, commercial and military careers offered attractive prospects. However, Rome put an end to sporadic uprisings – caused, amongst other things, by corrupt (Roman) officials – with ruthless violence.
Lugdunum, Augusta Raurica, and Avenches are examples of rapid Romanisation and decentralised administration in the Three Galliae. The Pax Romana of the early centuries of Roman rule changed Europe and the territory of present-day Switzerland forever.
Collection: Lugdunum-Musée et théâtres romains