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Hundred Days Offensive
August 8 – November 11, 1918· Battle· Europe
Well documentedSolid records, physical evidence or scientific consensus.
The final Allied offensive of World War I, which pushed the German army back across France and Belgium and forced the armistice.
See it on the Battles & Wars map →What happened
After Germany's spring offensives of 1918 failed, the Allies under supreme commander Ferdinand Foch struck back. At Amiens on August 8, British, Australian, Canadian and French troops with over 500 tanks advanced about 11 km in a day; German commander Erich Ludendorff called it 'the black day of the German army'. Repeated attacks, now joined by fresh American divisions, broke the Hindenburg Line in late September. Germany's allies collapsed, and it signed the armistice on November 11.
Why it matters
It ended the war on the Western Front by battlefield defeat. The myth that Germany was 'stabbed in the back' at home, not beaten in the field, later fed Nazi propaganda.
How we know
Allied and German operational records, Ludendorff's memoirs, prisoner counts in the hundreds of thousands, and unit histories of the Canadian and Australian corps.
Still debated
How much the victory owed to tanks, artillery tactics, American manpower or German exhaustion is still weighed differently by historians.
Connections (3)
▸Tank spearheaded Hundred Days OffensiveWell documented
The connection
At Amiens on August 8, 1918, over 500 tanks led the assault alongside infantry, artillery and aircraft, helping advance about 11 km on the first day. Later, tanks were fewer, as many broke down or were knocked out, but they kept helping infantry through wire and strongpoints, and German troops feared them.
When and how
Amiens, France, August 8, 1918, with the British Tank Corps, the Australian and Canadian corps and French tanks; then battles through the autumn.
How we know
Tank Corps records and German reports, including Ludendorff's memoirs, name tanks as a key factor in the Amiens breakthrough.
Debates and open questions
Some historians stress that artillery and infantry tactics, not tanks, won the Hundred Days; tank losses were heavy after the first days.
▸Hundred Days Offensive forced the armistice that ended World War IWell documented
The connection
By late September 1918, with the Hindenburg Line broken and Bulgaria out of the war, Ludendorff told Germany's leaders the war was lost and demanded an armistice. As Germany's allies collapsed and revolution spread at home, the Kaiser abdicated, and German delegates signed the armistice in a railway carriage at Compiègne on November 11.
When and how
The Western Front, August to November 1918; the armistice was signed in Foch's railway carriage in the Forest of Compiègne, taking effect at 11 am on November 11.
How we know
German high command records document Ludendorff's September 29 demand for an armistice after the military reverses.
Debates and open questions
How much the armistice came from battlefield defeat versus collapse at home is debated, a question that fed the postwar 'stab-in-the-back' myth.
▸Trench warfare was finally broken in Hundred Days OffensiveWell documented
The connection
By 1918 the Allies had learned to combine weapons: short surprise bombardments aimed by mapping and sound-ranging, creeping barrages, tanks, aircraft and small infantry units with light machine guns. These 'combined arms' tactics broke through trench systems again and again, ending four years of deadlock and returning the war to movement.
When and how
The Western Front, from Amiens on August 8, 1918, through the Hindenburg Line in late September, to the armistice.
How we know
Allied operational records and German accounts show trench lines broken repeatedly; captures of prisoners and guns soared in autumn 1918.
Debates and open questions
Historians debate whether this reflects a British 'learning curve' or mainly German exhaustion after the failed spring offensives.