How Allied forces united to win the war

After heavy losses in 1917, the Allies finally had unity of command and, with a million American troops on the Western Front by summer 1918, German resistance gradually collapsed

For the Allied armies, 1917 had ended on a grim note. Both the British and French armies had been badly damaged during their own offensives that year. This was particularly true in the case of the Nivelle Offensive, after which the French army mutinied, and the British 3rd Ypres (Passchendaele) Offensive, which had resulted in large casualties.

The massive tank attack at Cambrai in November had been a short-lived cause for celebration but a well-timed German counterattack drove the British forces out of any territory gained. Italy had nearly been knocked out the war during the Caporetto Offensive in October, while Russia was effectively out of the war following the Bolshevik Revolution.

America’s entry into the war was the cause of some optimism but it would be some time before the Americans arrived on the Western Front and could be made combat-effective. For the Allied political leaders and field commanders, the essential strategic question focused on how to hold on until the Americans arrived in numbers. In early 1918, the Middle Eastern and Italian fronts were stripped of French and British troops, while defences on the Western Front were strengthened in expectation of a German attack.

Russia's collapse in 1917 and the subsequent Treaty of Brest-Litovsk (March 3rd, 1918) freed up almost one million German troops from the Eastern Front. Gen Erich Ludendorff decided to use this numerical advantage to seize the initiative and launch a war-winning offensive in the west.


Using innovative artillery and storm-trooper tactics that had been perfected against the Russians, Ludendorff’s overall strategic plan was to separate the Allied armies by attacking at St Quentin. This French town was the vital hinge between the British and French forces. It was hoped the Germans could destroy the British Expeditionary Force (BEF) or force it to evacuate from the channel ports.

Peace settlement

This would surely result in a peace settlement on German terms. Often referred to as the “Kaiserschlacht” (the Kaiser’s Battle), the German offensive was in fact a series of operations that started with Operation Michael on March 21st and ran on in phases before ending with Operation Friedensturm (the “Peace Offensive”), which began on July 15th.

The German offensives met with initial success and the Allied formations were sorely pressed. Some French and British battalions simply disappeared under the weight of the German onslaught, while some veteran divisions, including the 16th Irish and 36th Ulster Divisions, were badly mauled. In terms of territorial gains, the German enjoyed their greatest success since 1914 and Paris came within range of their long range “super-gun”.

But ultimately the German operations ran out of steam as their logistical systems could not keep up with the advancing troops. Also, it became apparent the tactical methods were driving strategy. The German operations looked increasingly opportunistic and reactive while at the same time the Allied resistance strengthened.

In early April, Gen Foch was appointed as supreme commander or "generalissmo" of the Allied forces. At this late stage of the war, the Allies finally had unity of command and Foch would play a crucial role in co-ordinating the actions of army commanders such as Field-Marshal Sir Douglas Haig and Gen Philippe Pétain for the rest of the war.

As was the case in the desperate opening phases of 1914, the German advance was finally halted on the Marne. During the 2nd Battle of the Marne (July 15th- August 8th), French, British, American and Italian forces halted the Germans and began to roll their forces backwards. It was the beginning of the end of the war. By the summer of 1918, there were about one million American troops serving on the Western Front.

Despite the efforts of French and British commanders to use these troops to bolster their own flagging numbers, the American commander, Gen Pershing, was determined to field an independent US army. They would play a significant part in the final campaigns.

The Allies had been improving their own infantry and artillery tactics while they also struggled to tap the combat potential of the tank. A combination of new methods would be used to great effect in the upcoming battles. First World War tanks were slow and vulnerable but they could clear paths through barbed wire and destroy German pillboxes and MG positions. Infantry units now carried more light machine guns, light mortars, rifle-grenades and, in the French and US units, portable 37mm guns.

Infantry tactics

Infantry tactics were based on a system of laying down covering fire and then manoeuvring – tactics mirrored by modern armies. Artillery was used more intelligently to destroy key enemy positions in lightning barrages while providing a creeping barrage to protect the advancing infantry and tanks. Communications had improved and the Allied airforces had seized control of the air by the final phase of the war. This air dominance was a huge factor in the final victory.

The Battle of Amiens, which began on August 8th, 1918, is generally seen as the beginning of the final phase of the war, and marked the start of the "Hundred Days" cycle of battles. Using their new "combined arms" approach, the BEF forces broke through the German lines at Amiens, taking more than 50,000 Germans prisoners, along with much equipment.

Ludendorff, conscious the Allies had a successful format they would now repeat again and again, referred to it as a "black day" for the German army. For Germany, losses in manpower and equipment could no longer be replaced, while the Allied naval blockade was resulting in extreme privation on the home front. Allied success in breaching the formidable Hindenburg Line in late September underscored the gradual collapse of German resistance. Throughout the summer and autumn of 1918, Allied operations continued, gradually pushing the Germans back in the series of largely forgotten operations such as the battles of Belleau Wood, Albert, the Scarpe, St Mihiel, Courtai, among many others.

Facing military collapse

With political turmoil at home and facing military collapse, a German delegation under Matthias Erzberger left for France on November 6th, 1918. A series of tense negotiations took place in the forest at Compiène with Foch, who headed the Allied delegation, taking a particularly hard line.

The Allied demands essentially required the surrender of all significant military equipment and the withdrawal of German forces across the Rhine. Following the abdication of the kaiser and the establishment of a provisional socialist government, Erzberger signed the armistice terms on November 10th. This signalled a final ceasefire at 11am the following day. Despite the imminent ceasefire, some Allied commanders continued operations and many soldiers were killed within minutes of the ceasefire deadline. It is estimated that more than 2,700 soldiers died on the last day of the war.

While the Armistice was followed by huge public celebrations, it quickly became apparent that peace would bring its own challenges. Battle damage scarred whole areas across Europe and the other theatres of the war. In economic terms, the costs were crushing, with some nations only finally paying off first World War debts in recent years. In human terms, a whole generation had been killed or grievously wounded. It is estimated there were more than 17 million deaths, of which about seven million were civilians.

Despite the best of intentions, the subsequent peace conferences at Versailles and elsewhere did not ensure future peace and security. Indeed, before the war had even ended, the Allies were involved in a new expedition against Bolshevik Russia and further legacy campaigns emerged in the Middle East for both the French and the British. While the war may have ended, conflict continued and the fallout from the war drove extreme politics in the 1920s and 1930s. The "war to end all wars" had done nothing of the sort.

Martin Doyle VC

During the final 100 days offensive, Sgt Martin Doyle, from New Ross, Co Wexford, won the Victoria Cross. On September 2nd, Doyle, who was a sergeant in the Royal Munster Fusiliers, extricated a party of men who were surrounded by the enemy and brought a wounded officer to safety under heavy fire. He then returned to the battlefield and single-handedly took out a machine gun nest while capturing three prisoners.

After the war, Doyle turned against his former comrades and joined the IRA during the War of Independence. Later he joined the National Army. He died in 1940 at the age of 46 and is buried in Grangegorman Military Cemetery. It is customary for a VC winner to have it engraved on his headstone, but the British refused to grant him a military grave. Instead, the one in Grangegorman was erected by his comrades. Curiously, despite his involvement in Ireland’s national struggle, he died as a British soldier.

Dr David Murphy lectures in military history and strategic studies in Maynooth University