PLOMBIÈRES, CONGRESS OF. — Napoleon III’s personal policy, aimed on the one hand to secure the triumph of the principle of nationality in Italy and on the other to guarantee particular advantages for France and for his own family, led in 1858 to the Congress of Plombières, a spa town in the Vosges. There the Emperor of the French met secretly with Cavour and discussed the possibility of a military alliance with Piedmont against Austria.
The meeting, which took place on 21 July, lasted several hours. Before proceeding to examine the individual problems, Napoleon III expressed his prejudice against any realization of Italian unity by revolutionary means (the recent memory of Felice Orsini’s attempt on his life was still fresh), thereby implicitly aligning himself with the political platform of the Count of Cavour, which aimed to “diplomatize” the movement for Italian independence. To this declaration the Emperor of the French added further reservations: he could not consent to the dethronement of the Bourbons in the Kingdom of the Two Sicilies or that of the Pope in the Papal States, so as not to create difficulties in relations with Russia and not to alienate the support of French Catholics. Cavour accepted these reservations but countered with the possibility of proceeding to the annexation of the Legations, the Marches, and Umbria, while preserving for the Pope sovereignty over Rome and the Patrimony of St Peter. After this agreement on the limits of French support for the cause of Italian independence, Napoleon declared himself in favour of a settlement of the peninsula’s status with a kingdom of northern Italy under the Savoyard sceptre, comprising not only Piedmont but also Parma, Modena, Lombardy-Venetia, and the Legations. Tuscany, together with the Marches and Umbria, was in turn to form a kingdom of central Italy. The entire peninsula, together with the Kingdom of the Two Sicilies, would moreover constitute a confederation, whose presidency would be conferred upon the Pope. In compensation the Kingdom of Sardinia would cede Savoy to France, and King Victor Emmanuel II would grant his daughter Maria Clotilde in marriage to his cousin Jerome. The Congress of Plombières is particularly significant in the history of the papacy and of the movement for Italian independence and unity: without it the Second War of Independence of 1859 would never have broken out, and with it the critical phase of the Roman Question was opened.