Traces of life found in the south of Ille-et-Vilaine in Saint-Malo de Phily (North Brittany) provide evidence of human presence 600,000 years ago. Around 10,000 BC, a community using flint existed in Saint-Michel Chef-Chef (Loire-Atlantique, 40 km from Nantes), and other traces enable us to know that groups living on the coast in Finistère and Ille-et Vilaine had the same activities. In Plouézoc'h, a cairn (artificial pile of stones) (de Barnenez) was erected in 4,800 BC.
This was the Armorica peninsula, whose tin-rich ground enabled it to play a role during the 'Metal' ages. In Tréboul, Ploudalmezeau ...(Finistère), bronze storage sites were discovered which were in use in 1,400 BC. "Breton" type axes appeared. Natives travelled using dugout canoes to sell their production, which were the basis for the development of larger Venetii boats described by Julius Caesar.
Early writings from the beginning of our era, indicate how the Carthaginians discovered the 'Oestrymnides' islands (located in the Bay of Biscay and the Celtic sea close to the British Isles, possibly Ouessant), rich in tin used for making bronze. The Greeks also talk of the existence of the Celt, Enète and Istres peoples.
At the beginning of our era, agriculture and livestock farming now exist. Salt was an essential commodity, used for leather tanning and the conservation of meat and fish. Concentrated along the Southern shores of Armorica, salt was produced by heating brine in 'auget' ovens (link to glossary), and made into blocks to be sold or used for exchange.
Following the Roman occupation of Gaulle, salt continued to be an extremely important commodity, with a State monopoly controlled by conductores salinarium (or salt merchants). It was now a real industry, with factories comprising 4 to 16 cubic metre tanks. Concentrated in the bay of Douarnenez, the salt was used for conservation and for salting sardines to make garum (sauce, the main seasoning used in Rome after the Etruscan period and in Greece). At that time, the Armorica area was integrated into trade in the Roman Empire.
The end of the Empire led to anarchy and disorder. The Breton people arrived in Armorica from the Great Island (current Great Britain), either encouraged by Rome to repopulate a country devastated by the Saxons, or to occupy regions abandoned by the Romans.
During the second half of the 5th century, the Bretons signed a peace treaty with Clovis, giving them Osismes (Ossimi) and Coriosolites (Curiosolitae), as well as the status of independent Brittany. Immigration by Bretons intensified. They came with their saints (Samson, Léonor, Magliore, Brioc...), customs and traditions.