In accordance with the Treaty of Vienna, Austria cedes Veneto and Mantua to France, which immediately awards them to Italy in exchange for the earlier Italian acquiescence to the French annexation of Savoy and Nice.

The 1866 Treaty of Vienna was an agreement signed on 3 October 1866 and ratified on 12 October by the Kingdom of Italy and the Austrian Empire that concluded the hostilities of the Third War of Italian Independence, a theatre of the concurrent Austro-Prussian War.