Germany breaks off relations with Italy

The British chronology of the war records under 24 May 1915 that Germany broke off diplomatic relations with Italy. The day before, Italy had declared war on Austria-Hungary, but not on Germany, to which it had been bound for more than thirty years by the Triple Alliance. Berlin did not wait. According to Italian diplomatic documents published later, the German ambassador in Rome informed the Foreign Minister, Sidney Sonnino, that he was asking for his passports, since he had received word that Italy considered itself to be at war with Austria-Hungary. An identical note was delivered by the minister of Bavaria, which maintained its own legation in Rome.

The ambassadors leave

On 24 May Sonnino instructed the ambassador in Berlin, Riccardo Bollati, to ask for his passports as well. Bollati did so at once and left Germany early on 26 May. The protection of both countries’ interests was entrusted to Switzerland. According to a dispatch from the United States ambassador in Rome, the ambassadors of Germany and Austria-Hungary, both those accredited to the King and those accredited to the Pope, left Italy during the night of 24–25 May. As for Bülow himself, the sources differ: according to German accounts he left Rome by special train as early as the evening of 23 May, according to some studies only on 25 May. The American diplomat also reported that Rome and Berlin had agreed to respect private property and patent rights, and that civilians who committed no hostile acts would not be interned.

The failure of Bülow’s mission

Since December 1914 the German ambassador in Rome had been the former Reich Chancellor, Prince Bernhard von Bülow. He had been sent to the Tiber with a single task: to keep Italy neutral. Bülow knew Rome as few others did, had an Italian wife and a villa in the city, and was assisted by Matthias Erzberger, a deputy of the Catholic Centre Party. For several months he pressed Vienna to buy Italian neutrality with territorial concessions. Austria-Hungary finally agreed to give up the Italian part of the Tyrol and the west bank of the Isonzo with Gradisca, and to make Trieste a free city. But it was too late for these offers. In April Antonio Salandra’s government had bound itself to the Entente by a secret treaty, and at the beginning of May it had denounced the Triple Alliance.

A rupture without war

A peculiar situation arose. In the Treaty of London Italy had undertaken to wage war against all the enemies of the Entente, but it declared war only on Austria-Hungary. The government in Rome presented the war as the final act of the country’s unification, a fight for Trento and Trieste against the age-old enemy in Vienna. With Germany it had no border disputes, but strong economic ties. Germany, too, was in no hurry to declare war.

This did not mean that Germany would leave its ally on its own. At the end of May units of the newly formed German Alpine Corps (Alpenkorps) began arriving in the Tyrol. They were ordered not to enter Italian territory, but its soldiers were soon defending passes in the Dolomites alongside the Austrians. Italy declared war on the Ottoman Empire in August 1915, and on Germany only at the end of August 1916. According to the British chronology, for the purposes of the Treaty of Versailles it was later accepted that the rupture of relations had taken place on 27 May 1915, and that day was regarded as the beginning of the state of war between Italy and Germany.