The Nivelle Offensive (16 April – 9 May 1917) was a Franco-British operation on the Western Front in the First World War. The French part of the offensive was intended to be strategically decisive by breaking through the German defences on the Aisne front within 48 hours, with casualties expected to be around 10,000 men. A preliminary attack was to be made by the French Third Army at St. Quentin and the British First, Third and Fifth armies at Arras, to capture high ground and divert German reserves from the French fronts on the Aisne and in Champagne. The main offensive was to be delivered by the French on the Chemin des Dames ridge (the Second Battle of the Aisne, La bataille du Chemin des Dames, Seconde bataille de l'Aisne and Doppelschlacht Aisne-Champagne), with a subsidiary attack by