Between the signing of the sporazum on 20 August and its endorsement by the Skupština on 26 August 1939, Molotov and Ribbentrop concluded the Soviet-German Treaty of Non-Aggression (the so-called Nazi-Soviet Pact). Less than a fortnight later, on 1 September, the German invasion of Poland began. Paul at first imagined that he could keep out of the war until a suitable opportunity presented itself for Yugoslavia to join the Allied side. He believed that he could persuade the British and French to land at Salonika, with or without Greek and Italian consent, and that an Allied base on the Aegean would safeguard Yugoslavia's security and ensure the economic support necessary to break the German stranglehold on its economy. These hopes were based on the assumption that the Allies would have command of the Mediterranean and that the Italian fleet would be either neutralised or destroyed. A French military mission actually visited Belgrade and secret talks were opened with a view to coordinating plans. Hitler's successes in Norway and France in the spring of 1940 and Italy's declaration of war in June put an end to these pipe dreams. Yugoslavia was completely isolated and surrounded on all sides except the south by Axisoccupied countries or by regimes sympathetic to the enemy. Albania was under Italian control and was soon to become a base for the invasion of Greece. Austria was under Nazi occupation. Hungary, Romania and Bulgaria were moving towards the Axis.