Gaul as a nation was not a natural unit (Caesar differentiated between proper Gauls (Celtae), Belgae and Aquitani). In order to protect the route to Spain, Rome helped Massalia (Marseille) against bordering tribes. Following this intervention, the Romans conquered what they called "Provincia", or the "Province" in 121 BC. "Provincia" extended from the Mediterranean to Lake Geneva, and was later known as Narbonensis with its capital at Narbo. Some of the region falls into modern Provence, still recalling the Roman name.