known each other since meeting in 1908, when Bennett was living in France. War When Germany invaded France in 1914 Ravel tried to join the French Air Force. He considered his small stature and light weight ideal for an aviator, but was rejected because of his age and a minor heart complaint. While waiting to be enlisted, Ravel composed Trois Chansons, his only work for a cappella choir, setting his own texts in the tradition of French 16th-century chansons. He dedicated the three songs to people who might help him to enlist. After several unsuccessful attempts to enlist, Ravel finally joined the Thirteenth Artillery Regiment as a lorry driver in March 1915, when he was forty. Stravinsky expressed admiration for his friend's courage: "at his age and with his name he could have had an easier place, or done nothing". Some of Ravel's duties put him in mortal danger, driving munitions at night under heavy German bombardment. At the same time his peace of mind was undermined by his mother's failing health. His own health also deteriorated; he suffered from insomnia and digestive problems, underwent a bowel operation following amoebic dysentery in September 1916, and had frostbite in his feet the following winter. During the war, the Ligue Nationale pour la Defense de la Musique Française was formed by Saint-Saëns, Dubois, d'Indy and others, campaigning for a ban on the performance of contemporary German music. Ravel declined to join, telling the committee of the league in 1916, "It would be dangerous for French composers to ignore systematically the productions of their foreign colleagues, and thus form themselves into a sort of national coterie: our musical art, which is so rich at the present time, would soon degenerate, becoming isolated in banal formulas." The league responded by banning Ravel's music from its concerts. Ravel's mother died in January 1917, and he fell into a "horrible despair", compounding the distress he felt at the suffering endured by the people of his country during the war. He composed few works in the war years. The Piano Trio was almost complete when the conflict began, and the most substantial of his wartime works is Le tombeau de Couperin, composed between 1914 and 1917. The suite celebrates the tradition of François Couperin, the 18th-century French composer; each movement is dedicated to a friend of Ravel's who died in the war. 1920s After the war, those