Plombières Agreement of 1858

a secret pact between France and the Kingdom of Sardinia (Piedmont); signed in July in Plombières, France, by the French emperor Napoleon III and Prime Minister C. B. Cavour of Sardinia.

Under the accord, France was required to provide the Kingdom of Sardinia with military aid for the liberation of Lombardy and Venice from Austrian rule and the creation of a northern Italian state under the Savoy dynasty. The Kingdom of Sardinia pledged to turn over Savoy and Nice to France. However, after the War of Italian Liberation began in April 1859, Napoleon III, who was frightened by the growth of the national liberation movement in Italy and the threat of military intervention by Prussia, concluded the Treaty of Villafranca of 1859 in July with Austria. By the treaty, Venice was to remain under Austrian oppression.