On July 15, 1918, during World War I, the second Battle of Marne began. From the article:
"The Second Battle of the Marne lasted from July 15 to August 6, 1918, and was fought during World War I (1914-1918). Conceived as an attempt to draw Allied troops south from Flanders to facilitate an attack in that region, the offensive along the Marne proved to be the last the German Army would mount in the conflict. In the opening days of the fighting, German forces made only minor gains before being halted by a constellation of Allied troops.
Due to intelligence gathering, the Allies were largely aware of German intentions and had prepared a sizable counter-offensive. This moved forward on July 18 and quickly shattered German resistance. After two days of fighting, the Germans commenced a retreat back to trenches between the Aisne and Vesle Rivers. The Allied attack was the first in a series of sustained offensives that would bring the war to an end that November.
Spring Offensives
In early 1918, Generalquartiermeister Erich Ludendorff commenced a series of attacks known as the Spring Offensives with the goal of defeating the Allies before American troops arrived on the Western Front in large numbers. Though the Germans scored some early successes, these offensives were contained and halted. Seeking to continue pushing, Ludendorff planned for additional operations that summer.
Believing that the decisive blow should come in Flanders, Ludendorff planned a diversionary offensive at the Marne. With this attack, the hoped to pull Allied troops south from his intended target. This plan called for an offensive south through the salient caused by the Aisne Offensive of late May and early June as well as a second assault to the east of Reims.
German Plans
In the west, Ludendorff assembled seventeen divisions of General Max von Boehm's Seventh Army and additional troops from Ninth Army to strike at the French Sixth Army led by General Jean Degoutte. While Boehm's troops drove south to the Marne River to capture Epernay, twenty-three divisions from Generals Bruno von Mudra and Karl von Einem's First and Third Armies were poised to attack General Henri Gouraud's French Fourth Army in Champagne. In advancing on both sides of Reims, Ludendorff hoped to split the French forces in the area.
Allied Dispositions
Supporting the troops in the lines, French forces in the area were buttressed by approximately 85,000 Americans as well as the British XXII Corps. As July passed, intelligence gleaned from prisoners, deserters, and aerial reconnaissance provided the Allied leadership with a solid understanding of German intentions. This included learning the date and hour that Ludendorff's offensive was set to commence. To counter the enemy, Marshal Ferdinand Foch, Supreme Commander of the Allied forces, had French artillery strike the opposing lines as German forces were forming for the assault. He also made plans for a large-scale counter-offensive which was set to launch on July 18.
Armies & Commanders:
Allies
Marshal Ferdinand Foch
44 French divisions, 8 American divisions, 4 British divisions, and 2 Italian divisions
Germany
Generalquartiermeister Erich Ludendorff
52 divisions
The Germans Strike
Attacking on July 15, Ludendorff's assault in Champagne quickly bogged down. Utilizing an elastic defense-in-depth, Gouraud’s troops were able to quickly contain and defeat the German thrust. Taking heavy losses, the Germans halted the offensive around 11:00 AM and it was not resumed. For his actions, Gouraud earned the nickname the "Lion of Champagne." While Mudra and Einem were being halted, their comrades to the west fared better. Breaking through Degoutte's lines, the Germans were able to cross the Marne at Dormans and Boehm soon held a bridgehead nine miles wide by four miles deep. In the fighting, only the 3rd US Division held earning it the nickname "Rock of the Marne"
Holding the Line
The French Ninth Army, which had been held in reserve, was rushed forward to assist the Sixth Army and seal the breach. Aided by American, British, and Italian troops, the French were able to halt the Germans on July 17. Despite having gained some ground, the German position was tenuous as moving supplies and reinforcements across the Marne proved difficult due to Allied artillery and air attacks. Seeing an opportunity, Foch ordered plans for the counteroffensive to commence the next day. Committing twenty-four French divisions, as well as American, British, and Italian formations to the attack, he sought to eliminate the salient in the line caused by the earlier Aisne Offensive.
Allied Counterattack
Slamming into the Germans with Degoutte's Sixth Army and General Charles Mangin's Tenth Army (including the 1st and 2nd US Divisions) in the lead, the Allies began to drive the Germans back. While the Fifth and Ninth Armies conducted secondary attacks on the eastern side of the salient, the Sixth and Tenth advanced five miles on the first day. Though German resistance increased the next day, Tenth and Sixth Armies continued to advance. Under heavy pressure, Ludendorff ordered a retreat on July 20 (Map).
Falling back, German troops abandoned the Marne bridgehead and began mounting rearguard actions to cover their withdrawal to a line between the Aisne and Vesle Rivers. Pushing forward, the Allies liberated Soissons, at the northwest corner of the salient on August 2, which threatened to trap those German troops remaining in the salient. The next day, German troops moved back into the lines they occupied at the beginning of the Spring Offensives. Attacking these positions on August 6, Allied troops were repulsed by a stubborn German defense. The salient retaken, the Allies dug in to consolidate their gains and prepare for further offensive action.
Aftermath
The fighting along the Marne cost the Germans around 139,000 dead and wounded as well as 29,367 captured. Allied dead and wounded numbered: 95,165 French, 16,552 British, and 12,000 Americans. The final German offensive of the war, its defeat led many senior German commanders, such as Crown Prince Wilhelm, to believe that the war had been lost. Due to the severity of the defeat, Ludendorff cancelled his planned offensive in Flanders. The counterattack at the Marne was first in a series of Allied offensives that would ultimately end the war. Two days after the battle's end, British troops attacked at Amiens."