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.