Quadrilatero

thumb|right|The four fortresses of the Quadrilatero.

The Quadrilatero (, for greater specificity often called the "Quadrilateral fortresses") is the traditional name of a defensive system of the Austrian Empire in the Lombardy-Venetia region of Italy, which connected the fortresses of Peschiera, Mantua, Legnago and Verona between the Mincio, the Po, and the Adige Rivers. The name refers to the fact that on a map the fortresses appear to form the vertices of a quadrilateral. In the period between the end of the Napoleonic Wars and the Revolutions of 1848, they were the only fully modernized and armed fortresses within the Empire.