Post–World War I controversy over control of the Adriatic port of Fiume (modern Rijeka, Croatia).
The secret Treaty of London (1915) had assigned Fiume to Yugoslavia, but the Italians claimed it at the Paris Peace Conference . In 1919 Gabriele D'Annunzio mustered a small force and occupied Fiume. After Italy concluded the Treaty of Rapallo (1920) with Yugoslavia, which provided for a free state, it sent a battleship to scare him off. When Benito Mussolini came to power, he pressed for a new treaty (1924) that recognized Fiume as Italian and the suburb of Susak as Yugoslav. After World War II, Fiume became part of Yugoslavia.