The Fourth and Fifth Battles of Ypres tell the final 1918 chapter of the Ypres Salient: first a German offensive that erased much of the Allied 1917 gain, then an Allied advance that finally drove the German army east. The label “Fourth Battle of Ypres” is commonly used for the Flanders phase of the German Spring Offensive, also known as Operation Georgette or the Battle of the Lys, fought in April 1918. “Fifth Battle of Ypres” usually refers to the Allied offensive beginning on 28 September 1918 as part of the wider liberation of Flanders.

These battles are essential because they correct a common misconception about Passchendaele. The ridge captured at enormous cost in 1917 was not held permanently. In April 1918 the British shortened the Ypres Salient and lost much of that ground during the German offensive. Only months later did Belgian, British and French forces advance again. The battlefield therefore changed hands repeatedly right up to the final weeks of the war.

Why Germany attacked in 1918

Russia's withdrawal from the war allowed Germany to transfer divisions from the Eastern Front to France and Belgium. German leaders knew that American manpower would become increasingly important if the war continued. Their best opportunity appeared to be a major offensive before the balance became overwhelming.

On 21 March 1918 Operation Michael struck the British front on the Somme. The Germans advanced dramatically but failed to separate the British and French armies or capture Amiens. When Michael lost momentum, attention shifted north to Flanders.

Operation Georgette and the Battle of the Lys

The Flanders offensive is usually known as Operation Georgette or the Battle of the Lys. The National Army Museum dates the wider operation from 7 to 29 April 1918, with the main infantry assault beginning on 9 April.

The Germans attacked a sector south of Ypres held by British and Portuguese forces. Their aim included Hazebrouck, a vital railway centre. A successful advance could threaten the British armies' communications with the Channel ports.

The Portuguese front at Neuve-Chapelle

On 9 April the German assault fell heavily on the Portuguese 2nd Division near Neuve-Chapelle. The Portuguese had been in a difficult defensive situation and were due for relief. German forces achieved a major breakthrough and captured thousands of prisoners.

Older British narratives sometimes treated the Portuguese collapse dismissively. A fairer interpretation considers the scale of the attack, exhaustion of the defenders and concentration of German forces. The breakthrough created a crisis for the entire British front, not a simple national morality tale.

Why Haig wrote “backs to the wall”

As the German advance continued, Field Marshal Douglas Haig issued his famous Special Order of the Day on 11 April, telling troops that “every position must be held to the last man” and that with their backs to the wall each must fight on.

The phrase has become symbolic of British desperation in spring 1918. It reflected a genuine strategic danger. If Hazebrouck and the roads toward the Channel were lost, the British position in Flanders could become extremely difficult.

The Messines Ridge is lost again

One of the striking ironies of April 1918 is that ground captured in the carefully planned Battle of Messines in June 1917 had to be abandoned or was lost. British forces withdrew from exposed positions as the offensive developed.

For visitors this provides essential context. The Pool of Peace, Bayernwald and Messines Ridge are usually interpreted through 1917, but they also belong to 1918. Battlefield ground does not stop being historically active after its most famous battle.

Passchendaele gains abandoned

The British also shortened the Ypres Salient and gave up much of the eastern ground captured during Third Ypres. Maintaining the exposed ridge positions made little sense when the German attack threatened the entire Flanders front.

This did not mean every casualty of 1917 had been “for nothing” in a simple arithmetic sense, but it does demonstrate the danger of judging campaigns only by permanent possession of ground. Strategic situations changed.

Kemmelberg becomes the key

As the Germans advanced west and north, the Kemmelberg, or Mont Kemmel, became one of the most important heights in the region. It dominated the surrounding countryside and threatened Allied observation and communications.

German forces captured Kemmel on 25 April after severe fighting, including attacks against French troops brought into the sector. The fall of the hill was a dramatic success, but it did not produce the breakthrough to Hazebrouck.

Why the offensive stalled

German troops advanced into a landscape damaged by years of war. Roads were broken, rail links were limited and artillery had to be moved forward. Supply became more difficult with every kilometre gained.

Casualties also accumulated among the best assault troops. Allied resistance stiffened, reserves arrived and the attackers lost the surprise and momentum that had driven the first days.

The spring offensives exhausted Germany

Germany's 1918 offensives gained large areas of ground but did not destroy the Allied armies. The cost to trained assault formations was severe. Meanwhile American forces were arriving in greater numbers and Allied command became more coordinated under Marshal Ferdinand Foch.

By summer the strategic initiative began to shift. The German army was still dangerous, but it had fewer reserves and declining confidence.

From defence to Allied attack

The Allied counter-offensives began farther south, most famously with Amiens on 8 August 1918. German forces were pushed back across the Western Front in a series of operations known collectively as the Hundred Days.

In Flanders, a separate but coordinated offensive was prepared under the Army Group of Flanders. King Albert I of Belgium played a central political and command role, with Belgian, British and French armies cooperating.

28 September 1918: Fifth Ypres begins

The offensive began on 28 September. Belgian forces attacked from the north while British Second Army and French formations operated on adjacent sectors. The old Ypres battlefield was crossed once more.

Positions that had cost months to capture in 1917 could now fall more quickly because the German strategic situation was entirely different. Defensive morale, manpower and reserves were weaker, while Allied artillery, aircraft and logistics had improved.

Why the 1918 battlefield moved faster

Visitors often wonder why armies could advance rapidly over ground that had produced stalemate in earlier years. The answer is not one new weapon. It was the cumulative result of combined arms, better artillery methods, improved communications, tanks in suitable terrain, aircraft, logistical experience and a German army increasingly unable to replace losses.

By late 1918 trench systems could still be formidable, but the strategic balance had changed.

Ypres is finally released from the salient

For almost four years Ypres had sat close behind a dangerous front line. The September offensive pushed the fighting away from the city. The word “salient” finally ceased to describe the immediate Allied position around Ypres.

The psychological significance for Belgian civilians was enormous. The city was a ruin, but the military pressure that had defined it since 1914 was moving east.

The Belgian Army's role

The 1918 liberation of Flanders is sometimes told mainly through British Hundred Days narratives. Belgian troops were central in their own country. They had held the Yser front since 1914 and now advanced out of the defensive zone maintained for four years.

King Albert's position as commander of the Army Group of Flanders reflected both military and national significance. Liberation was not simply an Allied operation taking place on Belgian soil. It was also the recovery of occupied Belgium.

The British Second Army

General Herbert Plumer's Second Army, already associated with Messines and the September 1917 battles, again fought in Flanders during the final offensive. The army moved through ground deeply familiar from earlier campaigns.

That continuity provides a useful guide narrative: the same command that carefully captured ridges in 1917 returned in 1918 under completely different strategic conditions.

What “Fifth Battle of Ypres” actually means

Battle naming is not perfectly consistent across national histories. “Fifth Battle of Ypres” is widely used for the opening phase of the late-September Allied offensive, but broader sources may describe the campaign as the Ypres-Lys offensive or the liberation offensive in Flanders.

A good historical page should explain that variation rather than pretending one label is universal.

What happened after the first days?

The Allied advance continued through October toward Roeselare, Kortrijk and the Scheldt. German forces withdrew from successive defensive positions. Fighting remained hard and casualties continued right up to November.

The Armistice on 11 November ended the campaign before every military objective had to be fought out. Belgium emerged liberated but devastated.

The Ypres battlefield in 1918 looked different

Four years of shellfire had transformed the landscape. Roads had been rebuilt and destroyed repeatedly. Old trench systems were overgrown, collapsed or reused. New defensive positions cut across earlier battlefields.

Soldiers in 1918 could fight across cemeteries and ground already filled with unburied dead from earlier years. The battlefield literally contained the remains of previous campaigns.

How to visit the 1918 story today

Kemmelberg is the strongest landscape site for understanding Operation Georgette. Messines Ridge shows ground lost after the 1917 victory. Bayernwald provides the German trench perspective. Ypres itself shows the city that survived all the offensives without German occupation.

For the final Allied advance, the story extends beyond the classic tourist circuit around Ypres toward areas east and north-east of the city.

Why 1918 deserves more attention

Battlefield visitors naturally focus on 1915 gas warfare and 1917 Passchendaele. That can make the war seem as though it ended in mud. In reality, the final year was highly mobile. The German army came dangerously close to strategic success in spring and then suffered a series of defeats in autumn.

Understanding 1918 changes the whole Ypres narrative. The salient was not static for four years. It expanded, contracted and finally disappeared.

How civilians experienced the final year around Ypres

The military movement of 1918 also affected civilians who had already endured years of displacement. Villages south and west of Ypres again became threatened as the front moved. Families who had attempted to return to damaged homes could find themselves displaced a second time. Roads used by refugees also carried artillery, ammunition and reserves.

When the Allied advance began in September, liberation did not immediately mean normal life. Farms were mined or cratered, houses were ruined and roads were blocked by military traffic. The retreating German army removed or destroyed equipment and infrastructure where it could. The civilian recovery of West Flanders therefore began while military operations were still continuing farther east.

Why the April and September battles belong on one page

Separating the spring German attack from the autumn Allied advance can hide the most important lesson of 1918: the strategic balance changed with extraordinary speed. In April, British commanders feared that the Channel-port communications might be endangered. Less than six months later, the German army was retreating through Flanders.

Seeing both phases together also prevents Passchendaele from becoming the final chapter of the Ypres story. The war around Ypres ended not in the mud of November 1917, but in mobile operations during 1918.

Frequently asked questions

What was the Fourth Battle of Ypres?
The name is commonly used for the Flanders phase of the German Spring Offensive in April 1918, also called Operation Georgette or the Battle of the Lys.

Did Germany recapture Passchendaele in 1918?
The British shortened the salient and much of the ground won during Third Ypres was abandoned or lost during the German spring offensive.

What was the German objective in Flanders?
The offensive aimed to break the British front, threaten Hazebrouck and endanger British communications with the Channel ports.

What is the Fifth Battle of Ypres?
It is a common name for the Allied offensive that began on 28 September 1918 and pushed German forces away from Ypres during the liberation of Flanders.

Who led the Allied offensive in Flanders in 1918?
King Albert I of Belgium headed the Army Group of Flanders, which combined Belgian, British and French forces.

What are the best sites for the 1918 story?
Kemmelberg, Messines Ridge, Bayernwald and Ypres are among the clearest places to explain the spring crisis and the later liberation.