 By an 1858 secret agreement concluded at Plombières between Napoleon III of France and Sardinian prime minister Count Camillo Benso di Cavour, France agreed to support Piedmont in a war against Austria in order to wrest the provinces of Lombardy and Venetia from Austrian rule.In exchange for French military assistance, Piedmont was to cede Nice and Savoy to France.The annexation was temporarily put into doubt after the Italian war of 1859, during which Napoleon III concluded a separate peace with Austria before Venetia could be captured.