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 ( 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.
Controversies also debated 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.
Background
Flanders
1914
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.
1915
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.
1916
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.
Allied strategy
Nivelle planned preliminary offensives to pin German reserves by the British at Arras and the French between the Somme and the Oise, then a French breakthrough offensive on the Aisne, followed by pursuit and exploitation. Haig had reservations and on 6 January Nivelle agreed to a proviso that if the first two parts of the operation failed to lead to a breakthrough, the operations would be stopped and the British could move their forces north for the Flanders offensive, which was of great importance to the British government. On 23 January, Haig wrote that it would take six weeks to move British troops and equipment to Flanders and on 14 March, noted that the Messines Ridge operation could begin in May. On 21 March, he wrote to Nivelle that it would take two months to prepare the offensive from Messines to Steenstraat but that the Messines operation could be ready in five or six weeks.
The main French attack took place from 9 April to 9 May and failed to achieve a breakthrough. On 16 May, Haig wrote that he had divided the Flanders operation into two parts, one to take Messines Ridge and the main attack several weeks later. British determination to clear the Belgian coast took on more urgency after the Germans resumed unrestricted submarine warfare on 1 February 1917. On 1 May 1917, Haig wrote that the Nivelle Offensive had weakened the German army but that an attempt at a decisive blow would be premature. The wearing-out process would continue on a front where the Germans had no room to retreat. Even limited success would improve the tactical situation in the Ypres salient, reducing the exceptional wastage, even in quiet periods. In early May, Haig set the date for the Flanders offensive, the attack on Messines Ridge to begin on 7 June.
Kerensky offensive
The Russian army conducted the Kerensky Offensive in Galicia, to honour the agreement struck with the Allies at the Chantilly meeting of 15 to 16 November 1916. After a brief period of success from 1 to 19 July, the Russian offensive was contained by the German and Austro-Hungarian armies, which counter-attacked and forced the Russian armies to retreat. On the Baltic coast from 1 to 5 September 1917, the Germans attacked with their strategic reserve of six divisions and captured Riga. In Operation Albion (September–October 1917), the Germans took the islands at the mouth of the Gulf of Riga. The British and French commanders on the Western Front had to reckon on the German western army (Westheer) being strengthened by reinforcements from the Ostheer on the Eastern Front by late 1917. Haig wished to exploit the diversion of German forces in Russia for as long as it continued and urged the British War Cabinet to commit the maximum amount of manpower and munitions to the battle in Flanders.
Prelude
Ypres salient
Ypres is overlooked by Kemmel Hill in the south-west and from the east by a line of low hills running south-west to north-east. Wytschaete (Wijtschate) and Hill 60 are to the east of Verbrandenmolen, Hooge, Polygon Wood and Passchendaele (Passendale). The high point of the ridge is at Wytschaete, 7,000 yd (4.0 mi; 6.4 km) from Ypres, while at Hollebeke the ridge is 4,000 yd (2.3 mi; 3.7 km) distant and recedes to 7,000 yd (4.0 mi; 6.4 km) at Polygon Wood. Wytschaete is about 150 ft (46 m) above the plain; on the Ypres–Menin road at Hooge, the elevation is about 100 ft (30 m) and 70 ft (21 m) at Passchendaele. The rises are slight, apart from the vicinity of Zonnebeke, which has a gradient of 1:33. From Hooge and further east, the slope is 1:60 and near Hollebeke, it is 1:75; the heights are subtle and resemble a saucer lip around the city. The main ridge has spurs sloping east and one is particularly noticeable at Wytschaete, which runs 2 mi (3.2 km) south-east to Messines (Mesen) with a gentle slope on the east side and a 1:10 decline westwards. Further south, is the muddy valley of the River Douve, Ploegsteert Wood (Plugstreet to the British) and Hill 63. West of Messines Ridge is the parallel Wulverghem (Spanbroekmolen) Spur and on the east side, the Oosttaverne Spur, which is also parallel to the main ridge. The general aspect south and east of Ypres, is one of low ridges and dips, gradually flattening northwards beyond Passchendaele, into a featureless plain.
Possession of the higher ground to the south and east of Ypres, gives an army ample scope for ground observation, enfilade fire and converging artillery bombardments. An occupier also has the advantage that artillery deployments and the movement of reinforcements, supplies and stores can be screened from view. The ridge had woods from Wytschaete to Zonnebeke giving good cover, some being of notable size, like Polygon Wood and those later named Battle Wood, Shrewsbury Forest and Sanctuary Wood. In 1914, the woods usually had undergrowth but by 1917, artillery bombardments had reduced the woods to tree stumps, shattered tree trunks tangled with barbed wire and more wire festooning the ground, which was full of shell-holes; fields in the gaps between the woods were 800–1,000 yd (730–910 m) wide and devoid of cover. The main road to Ypres from Poperinge to Vlamertinge is in a defile, easily observed from the ridge. Roads in the area were unpaved, except for the main ones from Ypres, with occasional villages and houses dotted along them. The lowland west of the ridge was a mixture of meadows and fields, with high hedgerows dotted with trees, cut by streams and a network of drainage ditches emptying into canals.
Topography
In Flanders, sands, gravels and marls predominate, covered by silts in places. The coastal strip is sandy but a short way into the hinterland, the ground rises towards the Vale of Ypres, which before 1914 was a flourishing market garden. Ypres is 66 ft (20 m) above sea level; Bixschoote 4 mi (6.4 km) to the north is at 28 ft (8.5 m). To the east the land is at 66–82 ft (20–25 m) for several miles, with the Steenbeek river at 49 ft (15 m) near St Julien. There is a low ridge from Messines, 260 ft (80 m) at its highest point, running north-east past Clapham Junction at the west end of Gheluvelt plateau (2+1⁄2 miles from Ypres at 213 ft (65 m) and Gheluvelt, above 160 ft (50 m) to Passchendaele, (5+1⁄2 miles from Ypres at 160 ft (50 m) declining from there to a plain further north. Gradients vary from negligible, to 1:60 at Hooge and 1:33 at Zonnebeke.
Underneath the soil is London clay, sand and silt; according to the Commonwealth War Graves Commission categories of sand, sandy soils and well-balanced soils, Messines ridge is well-balanced soil and the ground around Ypres is sandy soil. The ground is drained by many streams, canals and ditches, which need regular maintenance. Since 1914 much of the drainage had been destroyed, though some parts were restored by land drainage companies from England. The British considered the area drier than Loos, Givenchy and Plugstreet Wood further south. A study of weather data recorded at Lille, 16 mi (26 km) from Ypres from 1867–1916, published in 1989, showed that August was more often dry than wet, that there was a trend towards dry autumns (September–November) and that average rainfall in October had decreased since the 1860s.