Kingdom of Italy

The Kingdom of Italy was a state which existed from 1861—when King Victor Emmanuel II of Sardinia was proclaimed King of Italy—until 1946—when civil discontent led a constitutional referendum to abandon the monarchy and form the modern Italian Republic. The state was founded as a result of the unification of Italy under the influence of the Kingdom of Sardinia, which can be considered its legal predecessor state.

Italy declared war on Austria in alliance with Prussia in 1866 and received the region of Veneto following their victory. Italian troops entered Rome in 1870, thereby ending more than one thousand years of Papal temporal power. Italy entered into a Triple Alliance with Germany and Austria-Hungary in 1882, following strong disagreements with France about the respective colonial expansions. However, even if relations with Berlin became very friendly, the alliance with Vienna remained purely formal as the Italians were keen to acquire Trentino and Trieste, corners of Austria-Hungary populated by Italians. So in 1915, Italy accepted the British invitation to join the Allied Powers, as the western powers promised territorial compensation for participation that was more generous than Vienna's offer in exchange for Italian neutrality. Victory in the war gave Italy a permanent seat in the Council of the League of Nations.

Wikipedia