On 10 May the Phoney War ended with a sweeping German invasion of the neutral Low Countries of Belgium, the Netherlands, and Luxembourg, and into France bypassing the French fortifications of the Maginot Line along the border with Germany. After overrunning the Netherlands, Belgium, and Luxembourg, Germany turned against France, entering the country through the Ardennes on 13 May—the French had left this area less well defended, believing its terrain to be impassable for tanks and other vehicles. Most Allied forces were in Flanders, anticipating a re-run of the World War I Schlieffen Plan, and were cut off from the French mainland. As a result of this, and also the superior German communications and tactics, the Battle of France was shorter than virtually all pre-war Allied thought could have conceived. It lasted only six weeks. On 10 June Italy declared war on both France and the United Kingdom but did not gain any significant success in this campaign. The French government fled Paris, and soon, France surrendered on 22 June. In order to further the humiliation of the French people and the country itself, Hitler arranged for the surrender document to be signed in the Forest of Compiègne, in the same railway coach where the German surrender had been signed in 1918. The surrender divided France into two major parts; the northern part under German control, and a southern part under French control, based at Vichy and referred to as Vichy France, a rump state friendly to Germany. Many French soldiers, as well as those of other occupied countries, escaped to Britain. The General de Gaulle proclaimed himself the legitimate leader of Free France and vowed to continue to fight. Following the unexpected swift victory, Hitler promoted 12 generals to the rank of field marshal during the 1940 Field Marshal Ceremony.