The first inhabitants of the Pays du St-Bernard were probably Etruscans, members of a northern Italian people.
Around 500 - 450 B.C. the Celts invaded the Po Valley. The Veragrians settled in the districts of Saint-Maurice, Martigny and Entremont.
After the annexation of Helvetia and the massacre of the Salassians (Celts from the Aosta Valley), the Romans decided to subjugate the Veragrians in order to secure sovereignty over the pass at Mons Jovis or Mont Joux (Great Saint Bernard).
When they entered the valley via Mons Jovis, they encountered four tribes:
- The Iberians to the east,
- the Seduns or "people of the hills" in the center, au center,
- the Veragrians on the axis of the Great Saint Bernard and
- the Nantuates in the Lake Geneva region.
These armed tribes founded densely populated centers that gave rise to Sedunum (Sion), Octodurum (Martigny) and Agaunum (Saint-Maurice).
They joined forces against the Roman invaders; an expedition by General Galba in 54 BC to occupy the Great Saint Bernard and the Simplon Pass failed and the legionnaires had to retreat.
After that, the Roman eagles, the Aquilæ, did not return until forty years later under Augustus.
Nothing is known about the living conditions under the Romans. On the other hand, we know that our valleys were devastated after the invasion of the barbarians, Huns and Saracens.
The Saracens destroyed the monastery - the refuge of Bourg-Saint-Pierre - and in 972 the Abbot of Cluny was captured at the bridge of Orsières.
The Pays du St-Bernard belonged to the first kingdom of Burgundy until 1032 and then to the county of Savoy.
In 1475, at the Battle of the Planta, the Valaisans were victorious and the Bishop of Sion became spiritual and temporal lord of Lower Valais, with a governor in Saint-Maurice and a castellan in Sembrancher. This is how it remained until the end of the Ancien Régime in 1798.
Then, after three years of independence and ten years as a department of the Simplon, the history of the Pays du St-Bernard became mixed with that of the Canton of Valais.