On 21 July, 1858, the secret meeting between Napoleon III and Piedmontese minister, Camillo Benso Cavour took place in the Vosges spa town of Plombières. As a result, the French emperor resolved to ‘liberate’ the Italian states from Austrian influence as part of his project to reunite France with Nice and Savoy. However, French intervention in Italy required the support, or at least the benediction, of Russia. The Prince Napoleon was sent to Warsaw to conduct secret preliminary meetings with Alexander II. The question remained however of how to follow up these meetings and get a man capable of conducting the discussions to St. Petersburg without arousing suspicion. The Prince Napoleon came up with the idea of Captain La Roncière Le Noury, who had commanded the warship Reine Hortense during the Prince’s scientific expedition in the North Sea in 1856. Napoleon III was very satisfied with the suggestion and indicated so in his letter: “My dear Napoleon, – I am delighted with your discovery. Arrange matters so that he leaves shortly.” (Letter from Napoleon III to the Prince Napoleon dated 31 October, 1858)
A document was drawn up detailing the financial and military arrangements between France and Piedmont in the event of ‘complications’ arising in the Italian states. The secret convention confirmed that a defensive and offensive alliance between Napoleon III and Victor Emmanuel II, king of Piedmont, Savoy, and Sardinia, would come into being in the case of Austria declaring war on the Piedmontese king. The convention, which also stated that Savoy and Nice would be reunited with France, was dated 16 December, 1858, although the possibility exists that it was actually signed later on, in January, but ante-dated, as argued by Ernest d’Hauterive. French intervention was dependent on Austrian aggression, however, and so Napoleon III was careful to remain discrete in his preparations and in his interaction with Austria.
