Third Italian War of Independence

The Third Italian War of Independence (Italian: Terza guerra d'indipendenza italiana) was a war between the Kingdom of Italy and the Austrian Empire fought between June and August 1866. The conflict paralleled the Austro-Prussian War and resulted in Austria giving the region of Venetia (present-day Veneto, Friuli and the city of Mantua, the last remnant of the Quadrilatero) to the Second French Empire (acting as intermediary in negotiations), which formally gave it to Italy.

Source: Wikipedia — Third Italian War of Independence (CC BY-SA 4.0)