It is certain that the crag was inhabited by prehistoric Man. However, it is impossible to precisely date the first lasting human establishment.
Archaeological discoveries in the neighborhood of La Balance reveal that the site was inhabited 4000 years B.C., by the Chaseens, whose civilization extended from central Italy to Burgundy. Raising livestock and cultivating the land, they are the founders of the first permanent settlements and villages in the region. The crag was a natural refuge from the numerous and violent caprices of the Rhone.

Towards the second millenium B.C., the Chalcalithic civilization settled here, along with the Campaniforme vase civilization. The first metal (brass) objects appeared. Archaeological discoveries reveal here farmer-breeders of a warlike temperament, who hunted as well.
An anthropomorphic monolith, (in the form of a man), dating from this period was uncovered in 1961. It is presently on view in the Calvet Museum.

Since High Antiquity, the indigenous people had contact with the Mediterranean civilizations. The Rhone constitutes a principal commercial route for the Greek and Phoenician sailors and Etruscan merchants. It is dotted with "oppida", fortified sites serving as storehouses and trading posts, and assuring surveillance of river traffic.

Following 500BC, the city extended considerably around the oppidum built on the cliff. The city was occupied by a celto-ligurian people - the Cavares.
The Phoenicians founded Massilia (Marseille) towards the 6th century B.C.. During the 4th century, the Greek colony contracted commercial agreements with the Cavares cities of Avignon and Cavaillon. These cities thus profited from The Marseille influence which extended throughout Southeast France.

The city's name originated from this era, "Aouen(n)ion", a name of Cavares origin, which has two interpretations : "City of violent wind," or "Lord of the River", according to either Celtic or Ligurian traduction. It seems, nonetheless, that the latter interpretation is more likely.