Major sources and definitions Geography Italy, slightly larger than Arizona, is a long peninsula shaped like a boot bounded on the west by the Tyrrhenian Sea and on the east by the Adriatic. The Alps form Italy's northern boundary. Italy has many northern lakes, lying below the snow-covered peaks of the Alps. The Po, the principal river, flows from the Alps on Italy's western border and crosses the Lombard plain to the Adriatic Sea.
Several islands form part of Italy.
From about the 9th century B.C. until it was overthrown by the Romans in the 3rd century B.C. , the Etruscan civilization dominated the area. By 264 B.C. all Italy south of Cisalpine Gaul was under the leadership of Rome. For the next seven centuries, until the barbarian invasions destroyed the western Roman Empire in the 4th and 5th centuries A.D. , the history of Italy was largely the history of Rome. From A.D. 800 on, the Holy Roman Emperors, Roman Catholic popes, Normans, and Saracens all vied for control over various segments of the Italian peninsula. Numerous city-states, such as Venice and Genoa, whose political and commercial rivalries were intense, and many small principalities flourished in the late Middle Ages.