Many contemporary Italian regions already had different substrata before the conquest of Italy and the islands by the ancient Romans: Northern Italy had a Ligurian, a Venetic, and a Celtic substratum in the areas once known as "Gallia Cisalpina" "Gallia on this side of the Alps"; Central Italy had an Umbrian and Etruscan substratum; Southern Italy and Sicily had an Oscan and Italic-Greek substratum respectively; and finally, Sardinia had an indigenous (Nuragic) and Punic substratum. These languages in their respective territories contributed in creolising Latin, the official language of the Roman Empire.