Greeks settled in the southern tip of the Italian Peninsula in the eighth and seventh centuries B.C.; Etruscans, Romans, and others inhabited the central and northern mainland. The peninsula subsequently was unified under the Roman Republic. The neighboring islands also came under Roman control by the third century B.C.; by the first century A.D., the Roman Empire effectively dominated the Mediterranean world. After the collapse of the Roman Empire in the West in the fifth century A.D., the peninsula and islands were subjected to a series of invasions, and political unity was lost. Italy became an oft-changing succession of small states, principalities, and kingdoms, which fought among themselves and were subject to ambitions of foreign powers. Popes of Rome ruled central Italy; rivalries between the popes and the Holy Roman Emperors, who claimed Italy as their domain, often made the peninsula a battleground.

The commercial prosperity of northern and central Italian cities, beginning in the 11th century, and the influence of the Renaissance mitigated somewhat the effects of these medieval political rivalries. Although Italy declined after the 16th century, the Renaissance had strengthened the idea of a single Italian nationality. By the early 19th century, a nationalist movement developed and led to the reunification of Italy--except for Rome--in the 1860s. In 1861, Victor Emmanuel II of the House of Savoy was proclaimed King of Italy. Rome was incorporated in 1870. From 1870 until 1922, Italy was a constitutional monarchy with a parliament elected under limited suffrage.

Italy allied with Germany and declared war on the United Kingdom and France in 1940. In 1941, Italy--with the other Axis powers, Germany and Japan--declared war on the United States and the Soviet Union. Following the Allied invasion of Sicily in 1943, the King dismissed Mussolini and appointed Marshal Pietro Badoglio as Premier. The Badoglio government declared war on Germany, which quickly occupied most of the country and freed Mussolini, who led a brief-lived regime in the north. An anti-fascist popular resistance movement grew during the last 2 years of the war, harassing German forces before they were driven out in April 1945. A 1946 plebiscite ended the monarchy, and a constituent assembly was elected to draw up plans for the republic.

Under the 1947 peace treaty, minor adjustments were made in Italy's frontier with France, the eastern border area was transferred to Yugoslavia, and the area around the city of Trieste was designated a free territory. In 1954, the free territory, which had remained under the administration of U.S.-U.K. forces (Zone A, including the city of Trieste) and Yugoslav forces (Zone B), was divided between Italy and Yugoslavia, principally along the zonal boundary. This arrangement was made permanent by the Italian-Yugoslav Treaty of Osimo, ratified in 1977 (currently being discussed by Italy, Slovenia, and Croatia). Under the 1947 peace treaty, Italy also relinquished its overseas territories and certain Mediterranean islands.

The Roman Catholic Church's status in Italy has been determined, since its temporal powers ended in 1870, by a series of accords with the Italian Government. Under the Lateran Pacts of 1929, which were confirmed by the present constitution, the state of Vatican City is recognized by Italy as an independent, sovereign entity. While preserving that recognition, in 1984, Italy and the Vatican updated several provisions of the 1929 accords. Included was the end of Roman Catholicism as Italy's formal state religion.

The musical influence of Italian composers Monteverdi, Palestrina, and Vivaldi proved epochal; in the 19th century, Italian romantic opera flourished under composers Gioacchino Rossini, Giuseppe Verdi, and Giacomo Puccini. Contemporary Italian artists, writers, filmmakers, architects, composers, and designers contribute significantly to Western culture.