When Germany invaded Poland on 1 September 1939 beginning World War II, Mussolini publicly declared on 24 September 1939 that Italy had the choice of entering the war or to remain neutral which would cause the country to lose its national dignity. Nevertheless, despite his aggressive posture, Mussolini kept Italy out of the conflict for several months. Mussolini told his son in law Count Ciano that he was personally jealous over Hitler's accomplishments and hoped that Hitler's prowess would be slowed down by Allied counterattack. Mussolini went so far as to lessen Germany's successes in Europe by giving advanced notice to Belgium and the Netherlands of an imminent German invasion, of which Germany had informed Italy.