World War I

Trench Warfare Begins

In the trenches: Infantry with gas masks, Ypres, 1917.

Trench warfare was the distinctive feature of the war. After the First Battle of the Marne, both Entente and German forces began a series of outflanking maneuvers to try to force the other to retreat, in the so-called Race to the Sea. The United Kingdom and France soon found themselves facing entrenched German positions from Lorraine to Belgium's Flemish coast. The United Kingdom and France sought to take the offensive, while Germany defended occupied territories.

One consequence was that German trenches were much better constructed than those of their enemy: Anglo-French trenches were only intended to be temporary before their forces broke through German defenses. Some hoped to break the stalemate by utilizing science and technology. In April 1915 the Germans used chlorine gas for the first time, which opened a 4 mile wide hole in the Allied lines when French colonial troops retreated before it. This breach was closed by allied soldiers at the Second Battle of Ypres where over five thousand, mainly Canadian, soldiers were gassed to death and Third Battle of Ypres, where Canadian forces took the village of Passchendale with the help of the Allied Powers.

Neither side proved able to deliver a decisive blow for the next four years, though protracted German action at Verdun throughout 1916, and the Entente's failure at the Somme in the summer of 1916, brought the exhausted French army to the brink of collapse. Futile attempts at frontal assault - with a rigid adherence to unimaginative maneuvers - came at a high price for both the British and the French poilu (infantry) and led to widespread mutinies, especially during the time of the Nivelle Offensive in the spring of 1917. News of the Russian Revolution gave a new incentive to socialist sentiments among the troops, with its seemingly inherent promise of peace. Red flags were hoisted, and the Internationale was sung on several occasions. At the height of the mutiny, thirty thousand to forty thousand French soldiers participated.

Throughout 1915-1917 the British Empire and France suffered far more casualties than Germany. However, while the Germans only mounted a single main offensive at Verdun, each failed attempt by the Entente to break through German lines was met with an equally fierce German counteroffensive to recapture lost positions. Around eight hundred thousand soldiers from the British Empire were on the Western Front at any one time. One thousand battalions, each occupying a sector of the line from the North Sea to the Orne River, operated on a month long, four stage rotation system, unless an offensive was underway. The front contained over six thousand miles of trenches. Each battalion held its sector for about a week before moving back to support lines and then further back to the reserve lines before a week out-of-line, often in the Poperinge or Amiens areas.

British 55th (West Lancashire) Division troops blinded by tear gas await treatment at an Advanced Dressing Station near Bethune during the Battle of Estaires, 10 April 1918, part of the German offensive in Flanders. Photographed by 2nd Lt. T.L. Aitken.

In the British-led Battle of Arras during the 1917 campaign, the only military success was the capture of Vimy Ridge by the Canadian forces under Sir Arthur Currie and Julian Byng. It provided the British allies with great military advantage that had a lasting impact on the war and is considered by many historians as the founding myth of Canada.