 After World War One and the breakup of the Austro-Hungarian Empire, the entire valley was occupied by the Italian Army, annexed to the Kingdom of Italy, and incorporated into the newly established Province of Gorizia.During the Fascist period (1922–1943), the people of the valley were subjected to a policy of violent Fascist Italianization, which triggered local resistance, both peaceful and violent (with the insurgent group TIGR).After 1941, the upper part of the valley became one of the first centers of Partisan resistance in Italy.