The Plombières Agreement (; ) of 21 July 1858 was a secret verbal agreement that took place at Plombières-les-Bains between the chief minister of Piedmont-Sardinia, Camillo Benso, Count of Cavour,President of the Council of Ministers of the Kingdom of Sardinia" ("Presidente del Consiglio dei ministri del Regno di Sardegna"). English-language sources tend to identify him simply as his country's "Chief minister" or "Prime Minister". and the French Emperor, Napoleon III. Some older English sources refer to it as the Treaty of Plombières. In modern times, it is merely referred to as an "agreement", since nothing was signed.
Based on limited available evidence, there have been disputes on the details of what was agreed upon at the meeting, but as years passed it became apparent that the agreement had opened the way for the , on 28 January 1859, and for the Second Italian War of Independence that became a vital step towards Italian unification, which was achieved within a decade of the agreement.
The Plombières Agreement was an agreement concerning a future war in which France and Piedmont would ally themselves against Austria to remove and exclude Austrian influence from the Italian peninsula. In its place, Italy, which Klemens von Metternich, a previous Austrian chancellor, had reportedly dismissed on various occasions as a "[mere] geographical expression", would be divided into two spheres of influence to be dominated respectively by Piedmont and France. As events turned out, the war was triggered as agreed at Plombières, but its geopolitical aftermath was not precisely the one that had been envisaged.
The French position Emperor Napoleon III was keen to settle the "Italian question" and to revise the humiliations of the 1815 Congress of Vienna. He had long ago formed the view that this required a war against Austria.Shared interests between the French and the liberal Lombard Federation had already been highlighted in 1849 by the nationalist historian Carlo Cattaneo in his 3 volume work on the 1848 revolution, "Storia della Rivoluzione del 1848", published in Lugano in 1849: «Rimovendo anche ogni geniale impulso, la Francia non poteva vedere con pace che le forze dell'Italia cadessero in mano di chi potesse torcerle contro di lei. … la Francia … sa d'avere nemici molti e potenti. Ora, i nemici suoi sono i nostri; noi siamo l'antiguardo del popolo francese.» War with Austria could bring France military success, delivering glory to France and humiliation to Austria. Actively supporting Italian nationalist aspirations would place France firmly on the side of what was then seen as progressive liberalism, and confirm the nation's special revolutionary credentials. For France, however, Italian independence and Italian political unification were two very different things. Political unification would have been contrary to French interests because it would have risked reducing French influence on the Italian peninsula.
Count of Cavour's opportunity The prime minister of Piedmont-Sardinia, Camillo Benso, Count of Cavour, was aware of the French objectives and was looking for an opportunity to serve these, while simultaneously achieving his goal of lifting the oppressive burden of Austrian rule from as many Italians as possible.
The arrival in Turin of Jacques Alexandre Bixio in April 1858 provided Cavour with his opportunity. Bixio was a retired physician, originally from Liguria, with a taste for politics and ballooning: he had made his life in France. Bixio was a friend both of Cavour and of Prince Napoléon-Jérôme Bonaparte, cousin to the French Emperor. His presence in Turin was ostensibly part of a discreet European tour, visiting various European royal families to find a socially suitable wife for the Emperor's cousin.
Bixio was also able to pass to his friend, the Piedmontese chief minister, French proposals for an alliance of the two states against Austria. The agreement would be reinforced through the marriage of Princess Maria Clotilde of Savoy, daughter of the Piedmontese king, Victor Emmanuel II, to Prince Napoléon-Jérôme.
Reflecting the international sensitivities involved, negotiations progressed outside the "usual" diplomatic channels. To confirm his approval of the proposal, Cavour sent his emissary, Costantino Nigra, to Paris, where Nigra made contact with another friend and confidant of the Emperor (and another physician) called Henri Conneau. On 9 May 1858, Conneau was able to confirm to Nigra that the alliance proposal had the full support of the Emperor himself. Further talks now took place in Turin involving Conneau, Cavour, and King Victor Emmanuel. At this point, a suggestion came from the Emperor for a meeting between himself and Cavour at Plombières-les-Bains, a fashionable health resort in the valley of the in the Vosges, reassuringly far from Paris or Turin, and off the beaten track of those following international diplomacy and politics.
The meeting On 11 July 1858 Count Cavour left Turin, letting it be known that he was heading for Switzerland. Only the King and the Piedmontese military commander, General La Marmora, were aware that his final destination was Plombières, where nine days later the Piedmontese prime minister arrived on the evening of 20 July 1858.
There is no surviving source for the meeting from Napoleon III. The only direct report of the discussions comes from Cavour. Cavour's report takes the form of a letter that he wrote to the King on 24 July 1858 from an overnight halt at Baden-Baden, while on his way home. This letter was made public in 1883 in La Perseveranza, a Milanese newspaper.
The meeting itself took place on 21 July 1858, with a first four-hour session starting at 11:00 and a second session running from 16:00 until 20:00. It was a Tuesday. The venue was a moving one: the two men sat together, without support staff, in a small horse-drawn carriage as it undertook a slow passage round and round the little town.
Searching for a casus belli
Neither man wanted the blame for causing the impending war. Cavour noted that Napoleon began by stating that he was determined to support Piedmont-Sardinia with all his strength in a war against Austria, on the condition that the war was not in support of a revolutionary causeIn his report of the meeting to his king Cavour entered parenthetically "(?!)" when reporting Napoleon's rejection of support for a "revolutionary cause". and could be justified in diplomatic terms and, more importantly, before public opinion in France and in Europe.«...risoluto a sostenere la Sardegna con tutte le sue forze in una guerra contro l’Austria, a patto che la guerra avvenisse per una causa non rivoluzionaria e potesse trovare giustificazione dinanzi alla diplomazia e più ancora all’opinione pubblica di Francia e d’Europa»...
Violations of trade treaty obligations by Austria were considered by Napoleon to be insufficient grounds for a war. This source includes a partial transcript of the text of Cavour's letter to the king reporting on his meeting with the French emperor. There was discussion of whether the presence of an Austrian military garrison in Bologna (in the Papal States) might justify war against Austria, but the French Emperor was in the end reluctant to use this as a pretext. There were Austrian troops not only in Bologna, but also in Rome and the Papal States, preserving the status quo; in Rome, there were also French troops for broadly similar reasons, and parallels between the garrisoning of Bologna and of Rome were uncomfortably close.
It then transpired that Napoleon had a proposal of his own. The Duchy of Modena and Reggio presented a more promising casus belli. Its ruler was Francis V, an Austrian ally and one of the many great-grandsons of the eighteenth-century Empress Maria Theresa. Francis had decided not to acknowledge Napoleon III as emperor of France following the latter's coup d'état at the start of the decade. Francis of Modena had inadvertently set himself up as eminently dispensable in the eyes of Napoleon. As they traveled round the streets of Plombières, Cavour and Napoleon devised a plan to provoke an appeal for protection from the Modenese citizens to the king of Piedmont-Sardinia, and a demand for the annexation of their duchy to Piedmont-Sardinia. The co-operation of the Modenese citizenry in such a scheme seems never to have been in doubt. The king of Piedmont-Sardinia would respond by graciously declining the appeal in the terms in which it was put, but he would nevertheless send a threatening communication to Francis V of Modena. The communication would be seen as interference in the Austrian sphere of influence and would provoke outrage in Vienna. As such, Austria's response would be correspondingly provocative. Piedmont-Sardinia would then find itself obliged to occupy Massa, a coastal city and an important port belonging to the Duchy of Modena, by which time a wider war with Austria would have been triggered.
A political structure for Italy Napoleon III stated that the Austrians must be completely ejected from the Italian peninsula, and Cavour agreed. The discussion then moved on to agreement on a political structure for the Italian peninsula following the removal of Austria. The existing Kingdom of Piedmont-Sardinia, together with the agriculturally rich Po Valley to the Soča river, and along with the entire northern (Romagna) part of the Papal States (the so-called "Papal Legations"), would become the Kingdom of Upper Italy ("Alta Italia"), under the king of Piedmont-Sardinia ("...sotto la guida di Vittorio Emanuele"). The southern part of the Papal States, with the exception of Rome and its immediate surrounds, was to be merged with the Grand Duchy of Tuscany in order to create a Kingdom of Central Italy ("Regno dell’Italia centrale"). The grand duke of Tuscany, Leopold II, another Austrian ally and great-grandson of Maria Theresa, would need to go. He would be replaced, at least on a provisional basis, by the (originally Francophone) Duchess of Parma Louise Marie of Artois. Napoleon had domestic reasons for displaying magnanimity to a descendant of the former Bourbon ruling dynasty: the appeal of traditional monarchism was far from dead in France. Rome and its immediate surroundings would continue to be ruled by the Pope. Further south, the Kingdom of the Two Sicilies should remain under the control of its existing king, Ferdinand II. Were Ferdinand to be removed from the scene the Emperor would be very happy for his successor to be his relative, Prince Lucien Murat. (Ferdinand II was known to be unwell: he would die within a year.) These four Italian states would have formed a confederation, modeled on the German Confederation, of which the honorary presidency would be given to the Pope.AA.VV, Storia delle relazioni internazionali, Bologna, 2004, pp. 45, 46.
The French price As Cavour later reported to his king,
"The Emperor asked me what France would get in return for her military backing, and whether Your Majesty would hand over Savoy and Nice to France. I replied that Your Majesty supported the principle of nationalism, which included recognition that Savoy, by virtue of being French-speaking, should be united with France ... even though it would cause your majesty untold unhappiness to renounce a territory that was the cradle of his own family. Regarding Nice, the situation was different, since the inhabitants of Nice had far more in common with the Piedmontese than with the French, and their incorporation into France would accordingly be entirely contrary to those very principles of nationalism underpinning the military triumph anticipated against Austria."