 Italy completed the unification by acquiring Trento and Trieste, and gained a permanent seat in the League of Nations's executive council.Nevertheless, Italian nationalists considered World War I a "mutilated victory" and that sentiment led to the rise of the fascist dictatorship of Benito Mussolini in 1922.The subsequent participation in World War II with the Axis powers, together with Nazi Germany and the Empire of Japan, ended in military defeat, Mussolini's arrest and escape (aided by the German dictator Adolf Hitler), and an Italian Civil War between the Italian Resistance (aided by the now-Allied Kingdom) and a nazifascist puppet state known as "the Italian Social Republic".