Switzerland in the Roman era

The mostly Celtic tribes of the area were subjugated by successive Roman campaigns aimed at control of the strategic routes from Italy across the Alps to the Rhine and into Gaul, most importantly by Julius Caesar's defeat of the largest tribal group, the Helvetii, in the Gallic Wars in 58 BC.

The Swiss plateau, within the natural borders of the Alps to the South and East, Lake Geneva and the Rhône to the west and the Rhine to the north, was recognized as a contiguous territory by Julius Caesar.

[1] This area had been dominated by the La Tène culture since the 5th century BC, settled by a mostly Celtic population (Gauls), of which the Helvetii were the most numerous, but which also included the Rauraci in north-west Switzerland centered on Basel, and the Allobroges around Geneva.

[3] In 61 BC, the Helvetii, led by Orgetorix, decided to leave their lands and move to the West, burning their settlements behind them – twelve oppida, according to Caesar, and some 400 villages.

[4] To that end, Caesar charged the Helvetii and the Rauraci with defending their territory and established two colonies of veterans – one, the Colonia Julia Equestris (now Nyon) on the shores of Lake Geneva and the other through Lucius Munatius Plancus in northwestern Switzerland, preceding the larger Augusta Raurica founded by Augustus in around 6 AD.

[5] Caesar's attempt to open the Great St Bernard Pass for Roman traffic failed in 57 BC due to strong opposition by the local Veragri.

[6] Concerted and successful efforts to gain control over the Alpine region were undertaken by his successor, Augustus, as the rapid development of Lugdunum (Lyon) made the establishment of a safe and direct route from Gaul to Italy a priority.

After a first expedition against them by Publius Silius Nerva in 16 BC, a more thorough campaign by Drusus and the later emperor Tiberius brought Raetia – and thereby all of Switzerland – firmly under Roman control.

[8] The principal Roman settlements in Switzerland were the cities of Iulia Equestris (Nyon), Aventicum (Avenches), Augusta Raurica (Augst) and Vindonissa (Windisch).

[12] Evidence has also been found of almost twenty Roman villages (vici) established in the 1st to 3rd century AD, as well as hundreds of villas of varying sizes built in the western and central part of the Swiss Plateau.

After Roman military defeats in Germania in 12–9 BC and 6–9 AD, the frontier was moved back to the Rhine and guarded by eight legions, of which one, originally Legio XIII Gemina, was based in the permanent camp of Vindonissa (Windisch).

[15] In the 40s, it benefited from the traffic brought over the St Bernard pass over a street expanded by Claudius,[15] and in 71 it acquired the status of a Roman colony and of an allied city.

[14] It remained essentially unchanged until Diocletian's reforms in the third century,[18] when parts of Switzerland each belonged to the provinces of Sequania, Vienna, Raetia Prima, Liguria and Alpes Graiae et Poeninae.

In that capacity, the magistrates of Aventicum, as duoviri coloniae Helvetiorum, also governed the entire Helvetic population, which had the legal status of incolae (inhabitants) invested with the Latin Right.

Artifacts related to the cults of gods such as Isis, Osiris, Serapis, Kybele, Serapios, Dionysos or Mithras have been found at the site of every Roman settlement in Switzerland.

In 260, when the Gallic Empire briefly seceded from Rome, the emperor Gallienus withdrew the legions from the Rhine to fight the usurper Ingenuus, allowing the warlike Alemanni to enter the Swiss plateau.

Urban culture faded away as the cities of Nyon and Augusta Raurica were permanently abandoned during the 4th century, the stones of their ruins serving to fortify Geneva and Basel.

These settlements established the most important cultural and linguistic division in modern Switzerland: the Burgundian areas eventually became the French-speaking Romandie, while the people in the larger Eastern half – called la suisse alémanique in French – still speak variants of Alemannic German.

Raetia maintained its Roman traditions longer than the rest of Switzerland, but most of it was eventually assimilated as well, leaving only a small territory where a Vulgar Latin dialect, Romansh, is spoken to this day.