Mare Nostrum (ˌmɑːrɪ_ˈnɒstrəm; Latin: "Our Sea") was a Roman name for the Mediterranean Sea. In Classical Latin, it would have been pronounced ˈma.rɛ ˈnɔs.t̪rʊ̃ː, and in Ecclesiastical Latin, it is pronounced ˈmaː.rɛ ˈnɔs.t̪rum.
In the decades following the 1861 unification of Italy, Italian nationalists and Italian fascists who saw Italy as the successor state to the Roman Empire attempted to revive the term.
The term Mare Nostrum originally was used by the Ancient Romans to refer to the Tyrrhenian Sea after their conquest of Sicily, Sardinia and Corsica during the Punic Wars with Carthage. By 30 BC, Roman dominion had extended from the Iberian Peninsula to Egypt, and Mare Nostrum began to be used in the context of the whole Mediterranean Sea. Other names were also employed, including Mare Internum ("Internal Sea"), but they did not include Mare Mediterraneum, which was a Late Latin creation that was attested to only well after the Fall of Rome.
In the decades following the 1861 unification of Italy, Italian nationalists who saw Italy as the successor state to the Roman Empire attempted to revive the term. In particular, the rise of Italian nationalism during the "Scramble for Africa" of the 1880s led to calls for the establishment of an Italian colonial empire, which introduced for the first time a renewed and modern concept of Mare Nostrum:
Even if the coast of Tripoli were a desert, even if it would not support one peasant or one Italian business firm, we still need to take it to avoid being suffocated in Mare Nostrum.
The term was again taken up by Benito Mussolini for use in fascist propaganda, in a similar manner to Adolf Hitler's Lebensraum. Mussolini wanted to re-establish the greatness of the Roman Empire and believed that Italy was the most powerful of the Mediterranean countries after World War I. He declared that "the twentieth century will be a century of Italian power" and created one of the most powerful navies of the world in order to control the Mediterranean Sea.