Born in Lille, he graduated from Saint-Cyr in 1912. He was a decorated officer of the First World War, wounded several times and later taken prisoner at Verdun. During the interwar period, he advocated mobile armoured divisions. During the German invasion of May 1940, he led an armoured division which counterattacked the invaders; he was then appointed Undersecretary for War. Refusing to accept his government's armistice with Germany, de Gaulle fled to England and exhorted the French to resist occupation and to continue the fight in his Appeal of 18 June. He led the Free French Forces and later headed the French National Liberation Committee against the Axis. Despite frosty relations with the United States, he generally had Winston Churchill's support and emerged as the undisputed leader of Free France. He became head of the Provisional Government of the French Republic in June 1944, the interim government of France following its Liberation. As early as 1944, de Gaulle introduced a dirigiste economic policy, which included substantial state-directed control over a capitalist economy which was followed by 30 years of unprecedented growth, known as the Trente Glorieuses. Frustrated by the return of petty partisanship in the new Fourth Republic, he resigned in early 1946 but continued to be politically active as founder of the Rassemblement du Peuple Français (RPF; "Rally of the French People"). He retired in the early 1950s and wrote his "War Memoirs", which quickly became a staple of modern French literature.