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Name

Hypotheses for the etymology of Italia are numerous. One theory suggests it originated from an Ancient Greek term for the land of the Italói, a tribe that resided in the region now known as Calabria. Originally thought to be named Vituli, some scholars suggest their totemic animal to be the calf (Lat vitulus, Umbrian vitlo, Oscan Víteliú). Several ancient authors said it was named after a local ruler Italus.

The ancient Greek term for Italy initially referred only to the south of the Bruttium peninsula and parts of Catanzaro and Vibo Valentia. The larger concept of Oenotria and "Italy" became synonymous, and the name applied to most of Lucania as well. Before the Roman Republic's expansion, the name was used by Greeks for the land between the strait of Messina and the line connecting the gulfs of Salerno and Taranto, corresponding to Calabria. The Greeks came to apply "Italia" to a larger region. In addition to the " Greek Italy " in the south, historians have suggested the existence of an "Etruscan Italy", which consisted of areas of central Italy.

The borders of Roman Italy, Italia, are better established. Cato's Origines describes Italy as the entire peninsula south of the Alps. In 264 BC, Roman Italy extended from the Arno and Rubicon rivers of the centre-north to the entire south. The northern area, Cisalpine Gaul, considered geographically part of Italy, was occupied by Rome in the 220s BC, but remained politically separated. It was legally merged into the administrative unit of Italy in 42 BC. Sardinia, Corsica, Sicily, and Malta were added to Italy by Diocletian in 292 AD, which made late-ancient Italy coterminous with the modern Italian geographical region.

The Latin Italicus was used to describe "a man of Italy" as opposed to a provincial, or one from the Roman province. The adjective italianus, from which Italian was derived, is from medieval Latin and was used alternatively with Italicus during the early modern period. After the fall of the Western Roman Empire, the Ostrogothic Kingdom of Italy was created. After the Lombard invasions, Italia was retained as the name for their kingdom, and its successor kingdom within the Holy Roman Empire.