The Second Battle of the Marne, 1918. US Forces Join the Allied Effort, Germany Flips from Offensive to Defensive, Starvation, Disease, Desertions, and Mutinies.

"How apt, if how strange, the historical coincidence by which, as the Marne had been the first high-water mark and witnessed the first ebb of the tide of invasion in 1914, so four years later it was destined to be the final high-water mark from which the decisive ebb began." From Lidel Hart in the Great War. 

And much like the Marne’s first confrontation, this battle of July 1918 would unfold with results that owed more to the chaotic whims of the battlefield than to any preordained plan. Let's now experience, the second battle of the Marne.

 Welcome to History's Greatest Battles, Season 01, Episode 74: the Second Battle of the Marne, the 15th through the 17th of July, 1918.

German Forces: as many as one point four million troops.
Allied Forces: roughly one million troops.

The last German offensive erupted with the desperation of a cornered power, a final, furious bid to break the stalemate. Yet, in this ultimate gambit, Germany unwittingly sealed its own fate, shifting the tides irreversibly toward Allied victory and signaling the end of an empire’s ambition amid the thunderous close of the Great War.

What began as a mere sideshow—intended to distract Allied forces from Germany’s true objectives—soon gathered a momentum all its own, drawing every soldier and strategist into a defining struggle. After three years of brutal trench warfare, Field Marshal Erich von Ludendorff had had enough. Now, he was preparing the strike to end the war once and for all, with Germany standing victorious over Europe.

With the Bolshevik Revolution in November 1917, Vladimir Lenin announced Russia’s withdrawal from the war. But when Germany demanded vast swaths of Russian land, Lenin resisted. German forces pushed on until March 1918, when Lenin, outmatched and unwilling to endure further attacks, signed the Treaty of Brest-Litovsk, handing over massive territory. With Russia out, hundreds of thousands of German troops were freed to flood the Western Front.

Officially, Ludendorff’s title was First Quartermaster General, but in reality, he held the reins of the entire German military. He crafted the campaigns of spring and summer 1918, each calculated to bring Germany ultimate victory. His plan aimed straight at the British in the north. A crushing blow there would unravel the Allied line—but first, he needed to draw French forces away from British positions. In March 1918, he launched the first of five calculated strikes.

Ludendorff knew that the old ways of warfare had run their course. He envisioned a radical change in tactics. In 1916, Russian General Alexei Brusilov had experimented with sending small, elite units into enemy lines to break through and disrupt the rear. But it was German General Oscar von Hutier who perfected this deadly art. Following closely behind a creeping artillery barrage, German stormtroopers would strike and cut off enemy supply lines, shattering reinforcements and paving the way for the larger forces behind them. British and French forces, unprepared for this style of warfare, could barely withstand the onslaught.

On March 21, 1918, the first German offensive hit along the Somme River. The results were staggering—the Germans hadn’t seen success like this since the earliest days of the war. The British Fifth Army was shredded, the assault sweeping across a front over 40 miles wide. Pushed back nearly 40 miles, the British fell into a desperate retreat, only halted when Allied reinforcements arrived. German forces, however, had stretched their supply lines too thin to sustain the assault. The cost was staggering: nearly a quarter-million casualties on each side. German forces used their advantage to bring in their terrifying new artillery—the infamous Paris Guns, 117-foot barrels that could rain shells from 80 miles away. Though physical damage to Paris was minimal, the psychological impact was profound.

British General Douglas Haig’s complaints that French General Henri Pétain was focusing too much on defending Paris sparked a pivotal change. On April 3, the Allies created the position of Supreme Commander and appointed French General Ferdinand Foch, uniting all Allied forces under one command for the first time.

For his second strike, Ludendorff zeroed in on an area he intended to make his final battleground. On April 9, German forces clashed with British positions along the Lys River, advancing again, though without the staggering success of March. Both sides bled heavily, each losing around 100,000 men in the brutal fighting. By late May, Ludendorff’s third offensive tore forward once more, capturing a massive piece of land and creating a salient 30 miles wide. German troops crossed the Aisne and Vesle Rivers, pressing within 20 miles of the Marne, closer to Paris than they had been since the war’s early days.

Fresh American forces arrived and met their first true test at Château-Thierry and Belleau Wood. They stood firm, halting the German advance with relentless counterattacks, even clawing back territory. Yet the success of this push forced Ludendorff to alter his strategy. He set aside his northern strike on the British, turning his focus south to Paris itself.

But trouble brewed for Ludendorff’s ambitions. The furious pace of each assault had bled his elite storm troopers dry. He had no choice but to revert to massed assaults, a tactic German soldiers—after three years of trench slaughter—had no stomach for. Desertions spiked, and disillusioned German soldiers began pouring into Allied lines, spilling secrets of the coming attack—times, locations, everything. So, when Ludendorff launched his fourth offensive on June 9, aiming southward along a line from Noyon to Mondidier, the Allies were prepared. French artillery opened fire first, tearing holes in the German advance before they even began. This preemptive barrage stalled the German advance and showed the Allies’ new defensive approach. They deployed only a thin screen of men up front, with their main forces entrenched further back, safely out of range. When German forces finally broke through, they soon slammed into a prepared, reinforced defense. After four days of grueling combat, they had little to show for it.

By now, Ludendorff could have moved to his grand assault against the British, but he gambled on one final feint to keep the French pinned down. His target was the city of Reims on the Vesle River, bypassed during the May and June offensives. Ludendorff ordered the Third Army to strike south, east of Reims, while the First and Seventh Armies advanced from the west. But once again, German deserters tipped off the Allies, who shut down the assault before it began. On the eastern front, the Third Army’s push fizzled, while the First and Seventh Armies managed to cross the Marne, only to find disaster waiting. Allied artillery and aircraft obliterated the Marne bridges as soon as the Germans crossed, leaving them stranded, cut off from supplies or reinforcements. The U.S. 3rd Infantry Division barred the German advance, forcing Ludendorff to order a retreat to defensive positions along the Vesle.

The Allies wasted no time. On July 18, General Foch—relentless in his belief in offensive action—unleashed the French Tenth and Fifth Armies in pursuit. Leading the charge were the U.S. 1st and 2nd Divisions, backed by six additional divisions across the front. This counteroffensive tore through German lines with such force that, by July 20, Ludendorff abandoned his planned northern assault entirely, realizing the offensive dream was dead.

By August 5, the Allies had reclaimed every inch of ground lost to the Germans since May and June. From this moment on, the once-fearsome German army was driven into a defensive crouch, unable to recover the initiative. Across five savage offensives, German forces had paid a staggering price—half a million men, dead, wounded, or captured. Ludendorff himself had called it der große Schlag—the “big push,” the blow that would win the war. But with the offensive now broken, morale across the German army collapsed.

Though the second Battle of the Marne didn’t deliver a full tactical victory, it gave the Allies the morale surge they’d been yearning for. The arrival of American troops brought more than just reinforcements—it stirred a wave of new confidence. Both Foch and British General Haig scrambled to integrate fresh American soldiers into their ranks. But General John Pershing, commanding the U.S. forces and backed by President Woodrow Wilson, stood firm: American troops would serve alongside the Allies, but as Americans, not simply as reinforcements. This decision came with sacrifice. In Belleau Wood and Château-Thierry, the Americans paid dearly, losing nearly half their forces between July 18 and August 5.

With Foch as supreme commander, the second Battle of the Marne marked the first true Allied effort as a unified force. Its success renewed their resolve. Only a year earlier, the French army had faced widespread mutinies fueled by the unending slaughter. Now, however, it was the German troops who began to lay down their arms. As the Allies closed in, collapsing the German salient between the Vesle and the Marne, the front—stagnant for nearly four years—began to shift.

The collapse at the Marne forced a bitter truth upon the German high command: victory was out of reach. On the home front, the German people were starving. War costs, coupled with an Allied blockade, had driven food supplies to crisis levels. The outbreak of a brutal influenza epidemic crippled Germany’s ability to arm and supply its forces. By August 8, Ludendorff knew the war was finished, yet it would be nearly two months before the German government formally requested peace talks on October 6.

President Woodrow Wilson, in a powerful rebuke, demanded Germany’s military leaders step down. Ludendorff resigned on October 27, and almost immediately, the German position unraveled further. The High Seas Fleet at Kiel mutinied, and Communist-inspired strikes erupted throughout Germany. By November 9, a socialist government had seized power, proclaimed a republic, and within two days, an armistice was signed on November 11. The peace that followed was a bitter one, punishing Germany with a severity that ignited a fierce desire for redemption—one that would, in time, set the stage for the Second World War.