Battle of Passchendaele

The Third Battle of Ypres (German: Dritte Flandernschlacht; French: Troisième Bataille des Flandres; Dutch: Derde Slag om Ieper), also known as the Battle of Passchendaele (/ˈpæʃəndeɪl/ PASH-ən-dayl), was a campaign of the First World War, fought by the Allies against the German Empire. The battle took place on the Western Front, from July to November 1917, for control of the ridges south and east of the Belgian city of Ypres in West Flanders, as part of a strategy decided by the Entente at conferences in November 1916 and May 1917. Passchendaele (now Passendale) lies on the last ridge east of Ypres, 5 mi (8 km) from Roulers (now Roeselare), a junction of the Bruges-(Brugge)-to-Kortrijk railway. The station at Roulers was on the main supply route of the German 4th Army. Once Passchendaele Ridge had been captured, the Allied advance was to continue to a line from Thourout (now Torhout) to Couckelaere (Koekelare).

Further operations and a British supporting attack along the Belgian coast from Nieuport (Nieuwpoort), combined with an amphibious landing (Operation Hush), were to have reached Bruges and then the Dutch frontier. Although a general withdrawal had seemed inevitable in early October, the Germans were able to avoid one due to the resistance of the 4th Army, unusually wet weather in August, the beginning of the autumn rains in October and the diversion of British and French resources to Italy. The campaign ended in November, when the Canadian Corps captured Passchendaele, apart from local attacks in December and early in the new year. The Battle of the Lys (Fourth Battle of Ypres) and the Fifth Battle of Ypres of 1918, were fought before the Allies occupied the Belgian coast and reached the Dutch frontier.

A campaign in Flanders was controversial in 1917 and has remained so. The British Prime Minister, David Lloyd George, opposed the offensive, as did General Ferdinand Foch, the Chief of Staff of the French Army. Field Marshal Sir Douglas Haig, commander of the British Expeditionary Force (BEF), did not receive approval for the Flanders operation from the War Cabinet until 25 July. Matters of dispute by the participants, writers and historians since 1917 include the wisdom of pursuing an offensive strategy in the wake of the Nivelle Offensive, rather than waiting for the arrival of the American Expeditionary Force (AEF) in France.

Remaining controversial are the choice of Flanders, its climate, the selection of General Hubert Gough and the Fifth Army to conduct the offensive, and debates over the nature of the opening attack and between advocates of shallow and deeper objectives. Also debated are the time between the Battle of Messines (7–14 June) and the first Allied attack (the Battle of Pilckem Ridge, 31 July), the extent to which the French Army mutinies influenced the British, the effect of the exceptional weather, the decision to continue the offensive in October and the human costs of the campaign.

Belgium had been recognised in the Treaty of London (1839) as a sovereign and neutral state after the secession of the southern provinces of the Netherlands in 1830. The German invasion of Belgium on 4 August 1914, in violation of Article VII of the treaty, was the British casus belli against Germany. British military operations in Belgium began with the arrival of the British Expeditionary Force (BEF) at Mons on 22 August. Operations in Flanders began during the Race to the Sea, reciprocal attempts by the French and German armies to turn their opponents' northern flank, through Picardy, Artois and Flanders. On 10 October, Lieutenant-General Erich von Falkenhayn, the Chief of Staff of the Oberste Heeresleitung (OHL, supreme army command), ordered an attack towards Dunkirk and Calais, followed by a turn south behind the Allied armies, to gain a decisive victory. On 16 October, the Belgians and some French reinforcements began the defence of western Belgium and the French Channel ports, at the Battle of the Yser. When the German offensive failed, Falkenhayn ordered the capture of Ypres to gain a local advantage. By 18 November, the First Battle of Ypres had also ended in failure, at a cost of 160,000 German casualties. In December, the British Admiralty began discussions with the War Office, for a combined operation to re-occupy the Belgian coast but were obliged to conform to French strategy and participate in offensives further south.

Large British offensive operations in Flanders were not possible in 1915, due to a lack of resources. The Germans conducted their own Flanders offensive at the Second Battle of Ypres (22 April – 15 May 1915), making the Ypres salient more costly to defend. Sir Douglas Haig succeeded Sir John French as Commander-in-Chief of the BEF on 19 December. A week after his appointment, Haig met Rear-Admiral Reginald Bacon, who emphasised the importance of obtaining control of the Belgian coast, to end the threat posed by German U-boats. Haig was sceptical of a coastal operation, believing that a landing from the sea would be far more difficult than anticipated and that an advance along the coast would require so much preparation, that the Germans would have ample warning. Haig preferred an advance from Ypres, to bypass the flooded area around the Yser and the coast, before attempting a coastal attack to clear the coast to the Dutch border.

Minor operations took place in the Ypres salient in 1916, some being German initiatives to distract the Allies from their preparations for the offensive at Verdun and later attempts to divert Allied resources from the Battle of the Somme. Other operations were begun by the British to regain territory or to evict the Germans from ground overlooking their positions. Engagements took place on 12 February at Boesinghe and on 14 February at Hooge and Sanctuary Wood. There were actions from 14 to 15 February and 1 to 4 March at The Bluff, 27 March – 16 April at the St Éloi Craters and the Battle of Mont Sorrel from 2 to 13 June. In January 1917, the Second Army (General Herbert Plumer) with the II Anzac, IX, X and VIII corps, held the Western Front in Flanders from Laventie to Boesinghe, with eleven divisions and up to two in reserve. There was much trench mortaring, mining and raiding by both sides and from January to May, the Second Army suffered 20,000 casualties. In May, reinforcements began arriving in Flanders from the south; the II Corps headquarters and 17 divisions had arrived by the end of the month.

In January 1916, Plumer began to plan offensives against Messines Ridge, Lille and Houthulst Forest. General Henry Rawlinson was also ordered to plan an attack from the Ypres Salient on 4 February; planning continued but the Battle of Verdun and the Battle of the Somme took up the rest of the year. In November, Haig, the French commander-in-chief Joseph Joffre and the other Allies met at Chantilly. The commanders agreed on a strategy of simultaneous attacks, to overwhelm the Central Powers on the Western, Eastern and Italian fronts, by the first fortnight of February 1917. A meeting in London of the Admiralty and the General Staff urged that the Flanders operation be undertaken in 1917 and Joffre replied on 8 December, agreeing to a Flanders campaign after the spring offensive. The plan for a year of attrition offensives on the Western Front, with the main effort to be made in the summer by the BEF, was scrapped by the new French Commander-in-Chief Robert Nivelle in favour of a return to a strategy of decisive battle.