was fought between September 6 and September 12. It started when retreating French forces (the Fifth and Sixth armies), stopped south of the Marne River. Victory seemed close, the First German Army was given orders to surround Paris, unaware the French government had already fled to Bordeaux. The First Battle of the Marne was a French victory, but was a bloody one: the French suffered 250,000 casualties, of which 80,000 died, with similar numbers believed for the Germans, and over 12,700 for the British. The German retreat after the First Battle of the Marne halted at the Aisne River, and the Allies soon caught up, starting the First Battle of the Aisne on September 12. It lasted until September 28, it was indecisive, partially due to machine guns beating back infantry sent to capture enemy positions. In the Battle of Le Cateau, fought on August 26–27, the French Sixth Army prevented the British from being outflanked. The first major Allied attack against German forces since the incarnation of trench warfare on the Western Front, the First Battle of Champagne, lasting from December 20, 1914, until March 17, 1915; it was a German victory, due in part to their machine gun battalions and the well-entrenched German forces. The indecisive Second Battle of Ypres, from April 22 – May 25, was the site of the first German chlorine gas attack and the only major German offensive on the Western Front in 1915. Ypres was devastated after the battle. The Second Battle of Artois, from May 9 – June 18, the most important part of the Allied spring offensive of 1915, was successful for the Germans, allowing them to advance rather than retreat as the Allies had planned, and Artois would not be in Allied hands again until 1917. The Second Battle of Champagne, from September 25 – November 6, was a general failure, with the French only advancing about , and not capturing the German's second line. France suffered over 140,000 casualties, while the Germans suffered over 80,000. The Battle of the Somme, fought along a front from north of the Somme River between Arras and Albert. It was fought between July 1 and November 18 and involved over 2 million men. The French suffered 200,000 casualties. Little territory was gained, only at the deepest points. Battle of the Frontiers The Battle of the Frontiers consisted of five offensives, commanded and planned