# Italo-Prussian alliance

The Italo-Prussian alliance was a military pact made by the Kingdom of Italy and the Kingdom of Prussia on April 8, 1866. It established the terms of the two nations' entry into the war against Austria and their respective compensations in case of victory. Italy would be compensated with Veneto (still Austrian); Prussia would receive comparable Austrian territories.
The alliance led to the Austro-Prussian War, known as the Third War of Independence on the Italian front. At the end of the conflict, as a result of Prussia's victories, and despite defeats at Custoza and Lissa, Italy obtained Veneto. Prussia instead extended its influence over all of Germany north of the Main River by leading the North German Confederation.

## Background (1859-1866)
### The attempts of Cavour and La Marmora

After the armistice of Villafranca (June 11, 1859), by which the Second War of Independence was concluded and it was decided to leave the Veneto region to Austria, Cavour sensed that the liberation of that province could take place through an agreement with Prussia. This nation, in fact, was also affected by the power of Austria, which at the Congress of Vienna had obtained in its sphere of influence the German Confederation.
Prime Minister Cavour (a few months before his death) in January 1861 sent General Alfonso Ferrero La Marmora to the Prussian capital Berlin with the official assignment of representing the Kingdom of Italy at the coronation of King William I. However, the mission also had the secret purpose of sounding out the Prussian government's intentions on a possible agreement against Austria. The mission was unsuccessful. The main reason was Prussia's conservatism, which distrusted a nation it considered too liberal.
In the period from 1861 to 1866 Italy made a few more attempts to obtain Veneto from Austria, which, not recognizing the new kingdom, forced the Italian government to seek mediation from France or Britain. To this end a first step was taken by Giuseppe Pasolini in December 1863 and a second by La Marmora in November 1864. Both attempts, however, did not yield useful results.
That was all until early October 1865, when Italian diplomacy took a final step to obtain Veneto without bloodshed. La Marmora authorized Count Alessandro Malaguzzi Valeri to begin secret negotiations with Austria, which was offered a large sum of money in exchange for the region. This mission also failed.

### Bismarck's moves

Three years after his rise to power in Prussia, Prime Minister Otto von Bismarck decided in 1865 to end Austrian influence over Germany with war. He therefore initiated exploratory contacts with France and Italy.
At the end of July 1865, he had one of his diplomats, Karl von Usedom, in Florence (the capital at the time), ask Prime Minister La Marmora what attitude Italy would take in the event of an Austro-Prussian conflict. La Marmora's answer was cautious: in order not to antagonize an old ally he declared that he could not make any commitments without knowing Napoleon III's intentions.
Questioned on August 13, 1865 on the subject by the Italian ambassador in Paris Costantino Nigra, French Foreign Minister Drouyn de Lhuys reported that France in the event of an Austro-Prussian war would remain neutral and that it would not oppose an Italian involvement in favor of Prussia.
Meanwhile, not at all discouraged by a climate that was becoming more relaxed between Prussia and Austria with the Gastein Convention, Bismarck confirmed in September to the Italian representative in Berlin Quigini Pulica that the final confrontation was only postponed. However, in order to enter the war without the danger of being attacked by neighboring powers, he secured Russia's benevolent attitude and Great Britain's disinterest. All that remained was to consult France as well.
This resulted in the meetings between Bismarck and Napoleon III in Biarritz and Paris in October and November 1865, during which the French emperor confirmed that he would maintain neutrality. In Paris, on November 2, 1865, Bismarck confided to Nigra that it was necessary to act quickly since Austria's finances were in bad shape, while Prussian finances were in better shape.
Upon his return from France, Bismarck provoked a deterioration in Austro-Prussian relations, first by provoking incidents in the Danish duchies that were the subject of the Second Schleswig War, and then, on January 26, 1866, by sending a harsh note of protest to Austria, accusing it of conspiring with the Augustenburgs, pretenders to the throne of the duchies. On February 7, the Austrian foreign minister, Alexander von Mensdorff-Pouilly, in turn protested Prussian interference in the administration of the Duchy of Holstein and the unsustainable climate created by Prussia. Finally, on February 28, 1866, in Berlin, the Prussian Privy Council decided on war with Austria and an alliance with Italy.

### The negotiations

During the Privy Council of February 28, 1866, Prussia decided to ask the Italian government to send an officer to Berlin to deal with the military matters of a possible alliance, while a Prussian officer would be sent to Florence. In Italy, the person in charge of the mission was General Giuseppe Govone, who arrived in Berlin on March 10, 1866.
The general, who left Florence with "few and general instructions", did not get a very encouraging impression from his first meeting with Bismarck. In fact, the Prussian prime minister offered him a general treaty with Italy, which, lacking any practical elements, seemed more likely to intimidate Austria in order to obtain advantages on the question of the Danish duchies.
In the same days, news came from St. Petersburg that Russia was opposed to a French proposal to grant the Danubian Principalities (increasingly independent of the Turkish protectorate) to Austria in exchange for Veneto to Italy. Similar concerns had also been expressed by the British Foreign Secretary George Villiers and the Austrian government.
Attention was once again focused on Bismarck and his proposal, the weakness of which was due to the fact that the Prime Minister was opposed to his war plans both at the court of Wilhelm I and in the country. For these reasons, Bismarck could not have concluded a reciprocal treaty with Italy with the aim of a decisive war, which La Marmora wanted instead. However, Napoleon III's encouragement to seize the opportunity and conclude a treaty convinced the Italians to abandon their reservations. Costantino Nigra wrote to La Marmora from Paris on March 23, 1866, that the Emperor advised Italy to accept the alliance with Prussia and that he would not allow Austria to attack Italy if Prussia then withdrew from the conflict.

### Signing and text of the treaty

On March 28, 1866, after seeing Bismarck's draft of the treaty, Prime Minister La Marmora telegraphed his representative in Berlin, Giulio De Barral, to inform him of the favorable impression the draft had made in Florence. On the 31st, another communication from Nigra to La Marmora conveyed Napoleon III's desire to start the war in order to find a way to extend France's borders on the Rhine; as well as an assurance that if Austria attacked Italy first, France would intervene against Austria.
The Italian-Prussian Treaty of Alliance was signed in Berlin on April 8, 1866 by De Barral and Govone for Italy and by Bismarck for Prussia. The text is as follows:
* Art. 1. There shall be friendship and alliance between H.M. the King of Italy (Victor Emmanuel II) and H.M. the King of Prussia (William I).
* Art. 2. Should the negotiations which H.M. the King of Prussia is about to enter into with other German Governments with a view to reforming the Federal Constitution in accordance with the needs of the German nation fail, and should H.M. consequently be in a position to take up arms in order to enforce his proposals, H.M. the King of Italy, upon the initiative of Prussia, as soon as he is informed of it, will declare war on Austria by virtue of the present Convention.
* Art. 3. From that time on, the war will be continued by T.M. with all the forces that Providence has placed at their disposal, and neither Italy nor Prussia will be able to conclude a peace or an armistice without mutual consent.
* Art. 4. Consent [to peace or armistice] shall not be refused if Austria has consented to cede to Prussia the Kingdom of Lombardy-Venetia and Austrian territories equal in population to the said Kingdom.
* Art. 5. This treaty shall cease to be in force three months after its signing if Prussia has not declared war on Austria in that time.
* Art. 6. If the Austrian fleet leaves the Adriatic before the declaration of war, H.M. the King of Italy will send a sufficient number of ships to the Baltic, where they will be stationed, ready to join the Prussian fleet as soon as hostilities begin.
As soon as the treaty was signed, Bismarck proposed to the Frankfurt Diet (the parliament of the German Confederation) that a directly elected assembly be convened to consider the proposals of the state governments for federal reform. The effect was intended to be devastating to Austria (leader of the Confederation), but instead the proposal was met with suspicion and sarcasm.

## The Austrian proposal to cede Veneto

As news of an Italo-Prussian treaty spread, Austria made several attempts to break the alliance. The most serious was a proposal to cede Veneto to France (Austria had no official relations with Italy) in exchange for French and Italian neutrality in the event of an Austro-Prussian conflict.
The proposal was made by the Austrian government to Napoleon III, who informed Nigra on May 4, 1866. The latter telegraphed La Marmora the next day. The offer was linked to the non-intervention of France and Italy in favor of Prussia and consisted of the following points:
* Cession of Veneto to France, which in turn would cede it to Italy (the cession would include all the fortresses of the Quadrilatero);
* Payment of a sum of money by Italy that would have been used for the construction of Austrian fortifications on the new border;
* All this after the Austrian occupation of the Prussian region of Silesia.
At first, the offer seemed attractive to La Marmora, especially since the recently concluded treaty with Prussia did not oblige Prussia to come to Italy's aid in the event of an attack by Austria. However, the proposal was not without its drawbacks. First, it would have violated a pact by making Prussia Italy's enemy. Second, Italy would have been indebted to France for the cession of Veneto. Third, Vienna's offer was tied to the Austrian occupation of Silesia, which seemed somewhat problematic.
Nevertheless, La Marmora wanted to sound out Prussia about its behavior in the event of an Austrian preemptive attack on Italy, so that he could decide on Vienna's offer with greater peace of mind. Ambassador De Barral replied on May 7 that both Bismarck and Wilhelm I had given assurances that Prussia would come to Italy's aid in the event of an Austrian attack, although this was not explicitly stated in the treaty. Thus reassured, and after a fruitful exchange of ideas between Govone and Nigra in Paris (both of whom were opposed to accepting the offer), La Marmora decided to reject the Austrian proposal: "[...] the government of Florence is determined not to go beyond the limits to which Prussia would be willing to go with regard to the commitments made with Italy", as he informed Govone, who, after arriving in the capital, left for Paris on the evening of the 14th.

## Napoleon III's moves

In addition to the Austrian proposal, the Italo-Prussian alliance faced another test. Napoleon III, who was apparently beginning to doubt the benefits France would gain from a war between Austria and Prussia, planned a European congress to address the outstanding problems: Veneto, the Danish duchies, and reform of the German Confederation. The Congress was also to discuss a neutral state on the Rhine in favor of France. Austria, which was offered unspecified compensations, was convinced that it would only get Silesia in exchange for Veneto by going to war. It therefore rejected the Congress and neutralized the French proposal.
Napoleon III, however, managed to extract an agreement from Vienna (June 12, 1866) to cede Veneto to him in the event of a victory over Prussia. In return, France would not intervene against Austria and would persuade Italy to do the same.

## The Austro-Prussian War

With France's promise of neutrality, Austria finally prepared for war. On June 1, 1866, in violation of the Treaty of Gastein, Austria declared that the Frankfurt Diet had jurisdiction over the Danish duchies. Prussia declared that the Gastein Convention had been violated and militarily occupied the Duchy of Holstein. The latter had been assigned to Austria by the treaty, and its troops withdrew without firing a shot. On June 12 (the day of the agreement with France), Vienna broke off diplomatic relations with Berlin and on June 14 submitted a motion to the Reichstag for federal mobilization against Prussia. Berlin then declared the German Confederation dissolved and on the 15th advanced its army southward, invading Saxony, which had sided with Austria. By the 16th, the conflict had indeed begun.
La Marmora sent the declaration of war to Vienna on June 20, 1866, with the date for the beginning of hostilities set for June 23. By the 21st, Prussian troops had arrived on Austria's northern border, while in Florence, appointed chief of staff and replaced in the government by Bettino Ricasoli, La Marmora was sent into the field and was defeated at Custoza on the 24th. On July 3, however, the Prussians won the battle of Sadowa, wiping out the Austrian main army. The war seemed to be coming to an early end.

### French mediation and the end of the war

The day before the defeat at Sadowa, the Austrians had already begun their second attempt to break the Italo-Prussian alliance. Warned by General Benedek of the impending military catastrophe, the Emperor of Austria, Franz Joseph, on the night of July 2 to 3, 1866, thought of immediately and unconditionally offering Veneto to Napoleon III in order to obtain an armistice with Italy. After Sadowa, on the 4th, he finally made this decision, which was communicated to the Austrian ambassador in Paris on the evening of the same day.
Napoleon III, who was beginning to seriously fear Prussian successes, telegraphed Victor Emmanuel II on July 5, offering him Veneto in exchange for peace with Austria. At the same time, he had the news published in the Moniteur.
The Italian government reacted very coldly to the initiative of Napoleon III, who nevertheless continued to put pressure on Victor Emmanuel II. For the Prime Minister Ricasoli, however, it was impossible to refuse the French mediation and he hesitated, trying to continue the war operations with maximum energy. Offered also to Prussia, Bismarck accepted the mediation of Napoleon III. It led to an agreement in principle between Austria and Prussia, which provided for the creation of a Prussian-led North German Confederation and the exclusion of Austria from all German affairs. After Vienna and Berlin accepted the plan, an armistice was signed.
The Italian army had meanwhile occupied Veneto, which the Austrians had abandoned, and was now approaching Trent. The armistice between the Austrians and the Prussians was agreed on July 21, to take effect at noon on July 22. The government in Florence learned of the agreement only indirectly, through France. Italy, however, was seeking a military victory, and in response to Napoleon III's demands for peace, the government replied that it was awaiting word from allied Prussia. But then, on July 22, news of the naval defeat at Lissa arrived, and the next day Italy also agreed to an armistice.
The cessation of hostilities began on the morning of July 25. By this time, Italian troops had occupied part of Trentino, and the Italian government was anxious to keep this territory, but Bismarck objected, claiming that he had accepted the French proposal for the integrity of the Austrian Empire except for Veneto. Italian Foreign Minister Emilio Visconti Venosta then postponed the armistice, hoping for a victory that would allow him to keep Trentino. However, with the signing of the peace preliminaries between Austria and Prussia on July 26, Italy sent its terms to France, a mediating power, on July 29. Austria refused to cede anything except Veneto, and Prussia refused to continue the war on Italy's side. The Italian troops in Trentino, commanded by Garibaldi and the Medici, were then recalled, and an armistice between Italy and Austria was concluded at Cormons on August 12, followed on October 3 by the Treaty of Vienna. It established the cession by France to Italy of only the region of Veneto. The Third War of Independence was over and with it the Italo-Prussian alliance.