Italian irredentism was a political movement during the late 19th and early 20th centuries in Italy with irredentist goals which promoted the unification of geographic areas in which indigenous peoples were considered to be ethnic Italians. At the beginning, the movement promoted the annexation to Italy of territories where Italians formed the absolute majority of the population, but retained by the Austrian Empire after the Third Italian War of Independence in 1866.

The Kingdom of Italy was a state that existed from 17 March 1861, when Victor Emmanuel II of Sardinia was proclaimed King of Italy, until 12 June 1946, when the monarchy was abolished, following civil discontent that led to an institutional referendum on 2 June 1946, which resulted in a modern Italian Republic. The kingdom was established through the unification of several states over a decades-long process, called the Risorgimento. That process was influenced by the Savoy-led Kingdom of Sardinia, which can be considered Italy's legal predecessor state.