Alanbrooke, Alan Francis Brooke, 1st Viscount Alanbrooke 1883-1963. British army officer, chief of staff in World War II and largely responsible for the strategy that led to the German defeat. He was born in Ireland. He served in the artillery in World War I, and in World War II, as commander of the 2nd Corps 1939-40, did much to aid the extrication of the British Expeditionary Force from Dunkirk. He was commander in chief of the Home Forces 1940-41 and chief of the Imperial General Staff 1941-46. He became a field marshal in 1944, was created a baron 1945 and viscount 1946.