Second Battle of the Marne The Second Battle of the Marne ( ) , or " Battle of Reims " ( 15 July – 6 August 1918 ) was the last major German Spring Offensive on the Western Front during the First World War . The German attack failed when an Allied counterattack led by French forces and including several hundred tanks overwhelmed the Germans on their right flank , inflicting severe casualties . The German defeat marked the start of the relentless Allied advance which culminated in the Armistice about 100 days later . Thus the Second Battle of the Marne can be considered as the beginning of the end of the Great War . Background . Following the failures of the Spring Offensive to end the conflict , Erich Ludendorff , Chief Quartermaster - General and virtual military ruler of Germany , believed that an attack through Flanders would give Germany a decisive victory over the British Expeditionary Force ( BEF ) , the most experienced Allied force on the Western Front at that time . To shield his intentions and draw Allied troops away from Belgium , Ludendorff planned for a large diversionary attack along the Marne . German attack . The battle began on 15 July 1918 when 23 German divisions of the First and Third armies — led by Bruno von Mudra and Karl von Einem — assaulted the French Fourth Army under Henri Gouraud east of Reims ( the Fourth Battle of Champagne ( ) ) . The U . S . 42nd Division was attached to the French Fourth Army and commanded by Gouraud at the time . Meanwhile , 17 divisions of the German Seventh Army , under Max von Boehn , aided by the Ninth Army under Eben , attacked the French Sixth Army led by Jean Degoutte to the west of Reims ( the Battle of the Mountain of Reims ( ) ) . Ludendorff hoped to split the French in two . The German attack on the east of Reims was stopped on the first day , but west of Reims the offensive fared better . The defenders of the south bank of the Marne could not escape the three - hour fury of the German guns . Under cover of gunfire , stormtrooper s swarmed across the river in every sort of transport — 30 - man canvas boats or rafts . They began to erect skeleton bridges at 12 points under fire from those Allied survivors who had not been suppressed by gas or artillery fire . Some Allied units , particularly the 3rd U . S . Infantry Division " Rock of the Marne " , held fast or even counterattacked , but by the evening , the Germans had captured a bridgehead either side of Dormans deep and wide , despite the intervention of 225 French bombers , which dropped of bombs on the makeshift bridges . The British XXII Corps and 85 , 000 American troops joined the French for the battle , and stalled the advance on 17 July 1918 . Allied counter - offensive . The German failure to break through , or to destroy the Allied armies in the field , allowed Ferdinand Foch , the Allied Supreme Commander , to proceed with the planned major counteroffensive on 18 July ; 24 French divisions , including the Buffalo Soldiers of the 92nd Infantry Division ( United States ) and 93rd Infantry Division ( United States ) under French command , joined by other Allied troops including eight large U . S . divisions under U . S . command and 350 tanks attacked the recently formed German salient . The new and highly effective Renault FT tanks were introduced on the battlefield for the first time . The Allied preparation was very important in countering the German offensive . It was believed that the Allies had the complete picture of the German offensive in terms of intentions and capabilities . The Allies knew the key points of the German plan down to the minute . By May , Foch had spotted flaws in the German offensives . The force which defeated the German offensive was mainly French , with American , British and Italian support . Co - ordinating this counter - attack would be a major problem as Foch had to work with " four national commanders but without any real authority to issue order under his own name [ . . . ] they would have to fight as a combined force and to overcome the major problems of different languages , cultures , doctrines and fighting styles . " However , the presence of fresh American troops , unbroken by years of war , significantly bolstered Allied resistance to the German offensive . Floyd Gibbons wrote about the American troops , saying , " I never saw men charge to their death with finer spirit . " On 19 July , the Italian Corps lost 9 , 334 officers and men out of a total fighting strength of about 24 , 000 . Nevertheless , Berthelot rushed two newly arrived British infantry divisions , the 51st ( Highland ) and 62nd ( West Riding ) , through the Italians straight into attack down the Ardre Valley ( the Battle of Tardenois ( ) — named after the surrounding Tardenois plain ) . The Germans ordered a retreat on 20 July and were forced back to the positions from which they had started their Spring Offensives . They strengthened their flank positions opposite the Allied pincers and on the 22nd , Ludendorff ordered to take up a line from the upper Ourcq to Marfaux . Costly Allied assaults continued for minimal gains . By 27 July , the Germans had withdrawn their center behind Fère - en - Tardenois and had completed an alternative rail link . The Germans retained Soissons in the west . On 1 August , French and British divisions of Mangin ' s Tenth Army renewed the attack , advancing to a depth of nearly . The Allied counterattack petered out on 6 August in the face of German offences . By this stage , the salient had been reduced and the Germans had been forced back to a line running along the Aisne and Vesle Rivers ; the front had been shortened by . The Second Battle of the Marne was an important victory . Ferdinand Foch received the baton of a Marshal of France . The Allies had taken 29 , 367 prisoners , 793 guns and 3 , 000 machine guns and inflicted 168 , 000 casualties on the Germans . The primary importance of the battle was its morale aspect : the decision gained on the Marne marked the end of a string of German victories and the beginning of a series of Allied victories that were in three months to bring the German Army to its knees .