Similarly, Amanda Grace Self (2016) stated that 'Rome's Etruscan Wars were not a simple process of expansion into barbarian-inhabited lands', but a complex series of disparate conflicts across centuries: 'The Romans had no notion of a planned, unified war against the Etruscan people. Rather, the military endeavors against the city-states of Etruria were discrete reactions to an array of individual factors and events. The Etruscans themselves never united in a large-scale war against the growing strength of Rome.' Rather than a single event, she wrote that the geographic proximity of the Romans and Etruscans as neighbours inhabiting opposite banks of the river Tiber naturally drove them to conflict over resources (such as the salt beds at the Tiber's mouth) and trade routes in the area, including the river itself for navigation. Usually, conflicts began with small-scale Etruscan raiding of the Roman countryside, and often ended in sieges of cities on either side.
