The original Roman city was situated west of the confluence of the Rhône and Saône, on the Fourvière heights. By the late centuries of the empire much of the population was located in the Saône River valley at the foot of Fourvière.
The Roman city was founded as Colonia Copia Felix Munatia, a name invoking prosperity and the blessing of the gods. The city became increasingly referred to as Lugdunum (and occasionally Lugudunum) by the end of the 1st century AD. During the Middle Ages, Lugdunum was transformed to Lyon by natural sound change.
Lugdunum is a latinization of the Gaulish *Lugudunon, meaning "Fortress (or hill) of (the god) Lugus" or, alternately "Fortress of the champion" (if *lugus is a common noun cognate with Old Irish lug "warrior, hero, fighter").
According to Pseudo-Plutarch, Lugdunum takes its name from an otherwise unattested Gaulish word lugos, that he says means "raven" (κόρακα), and the Gaulish word for an eminence or high ground (τοπον έξέχοντα), dunon.