On which side did Italy fight after entering World War I in 1915?

Italy fought on the side of the Allied Powers after entering World War I in 1915. Its decision was a major diplomatic reversal because Italy had previously belonged to the Triple Alliance with Germany and Austria-Hungary.

When war began in 1914, Italy remained neutral. The Italian government argued that the alliance was defensive and did not require support for Austria-Hungary’s offensive against Serbia. Italy also objected that Austria-Hungary had not properly consulted it before issuing its ultimatum.

Secret negotiations with the Allies produced the Treaty of London in April 1915. In exchange for territorial promises, including Trentino and Trieste, Italy declared war on Austria-Hungary on 23 May 1915. It later declared war on Germany in August 1916.

A common mix-up is assuming that Italy fought with the Central Powers because it had been allied with Germany and Austria-Hungary before the war. In practice, wartime alliances changed, and Italy’s entry opened a major front against Austria-Hungary along the Alps and the Isonzo River.