 The Etruscans extended this natural inland waterway with new canals to extend the navigation possibilities of the tidal reaches of the Po all the way north to Atria.As late as the time of the emperor Vespasian, shallow draft galleys could still be rowed from Ravenna into the heart of Etruria.Under Roman occupation the town ceded importance to the former Greek colony Ravenna as the continued siltation of the Po delta carried the seafront further to the east.