The dazzling Prussian victory at Sadowa erases the Italian defeat at Custoza

With three hundred thousand men on the battlefield of Sadowa (Königgrätz, attuale Hradec Králové) ill July 3, 1866 the Prussia decided in one fell swoop to expel Austria from the German Confederationthe assumption of the role of power that four years later would found the Second Reich and also the outcome of the third war of independence for Italy.

In reality the young kingdom of Savoy could have had the Veneto through diplomatic channels, because Austria could not afford a war on two fronts, and on 5 May 1866 it had shown its willingness to cede it to Napoleon III who would have turned it over to Vittorio Emanuele II. An indirect step because Vienna refused to recognize the Kingdom of Italy.

The diplomatic trap of the alliance desired by the cunning Bismarck

But on April 8 the crafty Prussian chancellor Otto von Bismarck had already bonded with a pact of «offensive and defensive alliance» between the Savoys and the Hohenzollernsthe content of which was totally in favor of Berlin: in the event of war, Italy would have to support Prussia, but Prussia would not have to do the same if the hostilities had been initiated or suffered by the Italians.

Austrian diplomacy in turn, on 12 June, had stipulated a secret pact with France to which he had offered the Veneto to pass to Italy if Napoleon III had managed to keep it from entering the war or, to save face, had led it “without too much effort”, and all this had been promptly reported to the ambassador Costantino Nigra. On 20 June, however, the declaration of war on Austria was officially forwarded, with the start of hostilities on the 23rd. Prussia, which had prepared that conflict in detail, had mobilized its formidable army since 3 May.

Berlin provides plans for the Savoy army which, however, will be disregarded

Berlin, in order to avoid surprises, had done even more: it had supplied through diplomatic channels two strategic war plans for Italyone of which envisaged an advance towards the Isonzo, through the Quadrilatero (Verona, Peschiera, Mantua and Legnago) and the other an offensive from the Lower Po through the Polesine, with a landing of Giuseppe Garibaldi’s volunteers in the upper Adriatic. It was clear that William I’s army in the north would win the war, excellently trained, modernly armed and effectively commanded by the Field Marshal Helmuth von Moltke.

The strategy had received the approval of Vittorio Emanuele II, Garibaldi and the commander of the 4th army Enrico Cialdini, but not of the chief of staff, general Alfonso La Marmora who until 17 June was Prime Minister (he assumed the new operational role only two days before the declaration of war), who he wanted to attack the Quadrilatero from the Mincio and not from the Po and he was a supporter of the division of the army, the first unitary, into two shock forces. In the clash with the Austrian army, Italy deployed 20 divisions, 12 entrusted to La Marmora and 8 to Cialdini, over 220,000 men.

“Our respective action – wrote La Marmora – was too obvious to discuss. Each on his side would have acted according to the circumstances with the necessary energy, in order to beat or paralyze the enemy by attracting him now to one side or to the other. Subsequently, and depending on the successes obtained, either the army would have reunited entirely on one side, or the Army of the Po would have been considerably strengthened, if it had succeeded (!) in conquering Rovigo and reaching the Adige. Only with these views the preliminary separation of the army into two fractions can be justified; and especially since each was stronger than the enemy field army”.

The rivalries between La Marmora and Cialdini and the absurdities in battle

A Custozawhere the Austrians of Archduke Albert of Habsburg-Teschen were 75,000, the defeat took place, which was not technically a defeat – in reality it was an incomprehensible retreat, so much so that the Austrians who suffered double the Italian losses did not even realize they had won – only due to the decisive intervention of the former Bourbon general Giuseppe Salvatore Pianell who took the initiative, averting total disaster and rout.

He behaved in the opposite way to the obtuse Giovanni Morozzo Della Rocca who instead entrenched himself on the orders received and did not budge even at the direct request of Vittorio Emanuele to throw his soldiers into the fray. La Marmora, who lost his lucidity, used the words “irreparable disaster” with the king and so in a telegram to Garibaldi. The Prussians are baffled: perhaps the Italians are really waging that war “without much effort”. Instead, they put in their commitment at the highest levels at Sadowa, on 3 July, defeating the Austrians and the Saxon allies and inflicting a decisive defeat that opens the way to Vienna is open to the army with the spiked helmet. Franz Joseph must take action.

Napoleon III and the cession of the Veneto as “assent” of Franz Joseph

Habsburg diplomacy then asks Napoleon III to promote Italy’s exit from the war with a bilateral armistice ceding the Veneto to him as a pledgeand the emperor communicated it on July 5th by telegram to Vittorio Emanuele, only he also let the French press know and it was a bad move. To save face and gain time, Italy will seek revenge on land, where it is possible to achieve tactical success because the army is practically intact, and unfortunately also on the sea, where instead on July 20 the modern fleet of Admiral Carlo Pellion of Persano will be torn to pieces in Lissa.

Game closed. Berlin then does everything itself, the next day grants Austria a truce and begins diplomatic negotiations. The Official Journal thus reports a bulletin dated 24 July: “The negotiations between Prussia, France and Austria on the conditions of the armistice have ended. Prussia accepts the integrity of the Austrian Empire, excluding the Veneto, and requests that the Italian Government agrees to the suspension of hostilities”. On the 26th the Austro-Prussian armistice was signed in Nikolsburg, which also effectively concluded the alliance with Italy.

Garibaldi’s Cacciatori delle Alpi are stopped and so is the regular army, and on 3 August the front is frozen, prior to the withdrawal to the Veneto by the 11th, cutting off Trentino from the negotiations. To make his moves, Bismarck neither consulted nor informed his Italian ally. The peace between the Kingdom of Prussia and the Empire of Austria was signed on 24 August in Prague, and Italy obtained a territorial enlargement through Napoleon III, bringing the borders to the 1815 line between Lombardy-Veneto and Austria. The signing of the Peace Treaty will take place in Vienna on 3 October. The Veneto will be ceded by France to Italy on 19 October in a room at the Hotel Europa in Paris. Two days later referendum foreseen by the clauses will sanction the transition to the Kingdom of Italy with 641,758 yes (99.99%)just 69 no and 273 abstentions. But in the peace treaty Franz Joseph had used the restrictive formula of “assent to the reunification of the Lombardy-Veneto kingdom with the kingdom of Italy”.