One for all, all for one: first World War Allies agree military strategy

The deadly battles of Verdun, the Somme, and Salonika were fought in solidarity by the Allies to take pressure off each other

In late 1915, Allied leaders met to decide their strategy for the following year. It had been a year of disappointments characterised by high casualties, shortages in war materiel and growing political and public discontent about how the war was being conducted. Large-scale offensives on the Western Front had failed while an alternative strategy to take the Ottoman Empire out of the war had resulted in the disastrous Gallipoli campaign.

A further Allied expedition to Salonika, initiated in October, was currently stalled while there were also setbacks in Mesopotamia (modern-day Iraq). This lack of success came with casualty figures that were simply staggering. By the end of 1915, the French had had more than two million killed, wounded, prisoners and missing while Britain had had more than 600,000 casualties. Russia had suffered more than 3.8 million total casualties.

On December 4th, 1915, Lord Kitchener, the British minister for war, and General William Robertson, chief of the Imperial General Staff, met the French premier, Aristide Briand and General Joseph Joffre, the French commander-in-chief, at Calais.

It was intended that this meeting would sort out French and British priorities for 1916 but the main focus became the Salonika operation. After some debate, it was decided to suspend operations on that front. Just two days later, however, a further conference was held at Chantilly and it was decided to continue operations in Salonika.


This decision signalled the final death knell for the Gallipoli campaign as it would be impossible to continue operations there while also reinforcing the Salonika front. In attendance at this meeting was also Lord French, who was then British commander-in-chief, but he was soon to be replaced by Field-Marshal Sir Douglas Haig. Representatives from Russia, Serbia and Italy also attended.

A broad strategy of co-operation was agreed upon with plans made for offensives on the Western Front, the Eastern Front, Italy and Salonika during 1916. The Russian representative, General Yakov Zhilinksi, complained about the lack of co-ordinated efforts in 1915, pointing out how Russia had been left to face the Central Powers’ “Triple Offensive” in the summer of 1915, without its French and British allies mounting diversionary offensives on the Western Front.

As a result of these debates, each Allied nation agreed to mount an offensive of its own if one of the other allies should become the target of a German or Austro-Hungarian attack. It was a crucial decision and this agreement would dominate how military operations unfolded in 1916.

While the Allies were discussing their plans for 1916, the Central Powers were, obviously, doing the same and they seized the strategic initiative early in the year. Their plans were driven by similar pressures as public discontent was growing in Germany about the conduct of the war while the casualty figures mounted.

By the end of 1915, the Germans had suffered more than 2.8 million casualties whereas the Austro-Hungarians had lost more than 2.5 million. Their land operations had failed to bring victory and while U-Boat and Zeppelin operations were challenging the Allies, the Central Powers needed a decisive victory.

The German chief-of-staff, General Erich von Falkenhayn, conceived a plan that would end the war with a German victory, and he outlined his intentions in a letter to Kaiser Wilhelm, sent on Christmas Day 1915. Russia, Falkenhayn argued, was on the verge of collapse while Britain should be made the target of a campaign of unrestricted submarine warfare. The main focus of offensive operations should be against France in the belief that, if France was taken out of the war, Britain would have to pursue a separate peace.

His plans were given broad approval and Falkenhayn decided to focus his efforts against the fortified city of Verdun – a target that the French would feel obliged to defend. In drawing the French into this attritional contest, Falkenhayn believed that he could “bleed France white” and thus end the war. For some reason, Falkenhayn does not seem to have factored in the attrition that would be inflicted on the German army.

The Battle of Verdun began on February 21st, 1916, and continued until December 18th, arguably making it the longest battle in history. For the initial attack, the Germans assembled vast artillery assets and opened the offensive with a 21-hour bombardment that fired more than one million rounds into the French defences.

The German Fifth Army, under Crown Prince Wilhelm, consisted of around one million troops while the French had only 200,000 defenders in place. Furthermore, the city’s defensive forts had been stripped of many of their heavy guns.

Despite their local superiority, the Germans found the going far from easy. Early successes pushed the French back to their second line of defences and the fort of Douaumont fell on February 25th. The loss of this fort, despite being an obsolete concept in the context of the first World War, served to galvanise France.

The French government, army and people were determined that Verdun could not be allowed to fall and the stage was set for the titanic struggle that unfolded during 1916. General Pétain was given control of the Verdun sector on February 24th and by concentrating his artillery reserves, he managed to halt the German advance. Thereafter, the battle continued in phases throughout the spring and summer with occasional lulls as both sides ran out of both men and materiel to continue the battle.

As part of the wider German strategy, the German Imperial Navy sortied its fleet in late April for the “Lowestoft raid” and again on May 31st for an operation that would result in the Battle of Jutland. While Jutland had significant strategic potential, it ended inconclusively and these efforts to put the British navy under pressure had little impact on affairs at Verdun as the battle developed into what veterans later referred to as “the meat grinder”.

In an effort to protect his units from long-term attrition, Pétain devised a system to rotate French divisions quickly in and out of the battle. It was later calculated that, of the 330 infantry regiments in the French Army, 259 of these fought at Verdun. For the French army and the French nation, Verdun became the defining battle of the war. Positions such as Mort Homme Hill and Fort Vaux became the focus of desperate defences by the French and, having lost them, even more ferocious counterattacks. Supreme efforts were made to maintain the embattled French army by ferrying fresh troops and supplies along a single route that came to be known as the “Voie Sacrée”; this was the first time that an army was sustained in the field by lorried transport.

The character of the battle was particularly brutal, with intensive artillery and also use of flamethrowers and gas. Some units, on both sides, were simply shelled into oblivion while the fighting within the forts was hellish during the sweltering summer months.

During July, the battle petered out due to heavy losses and also the manpower demands of offensives elsewhere, including the Somme. In August, the German high command ruled out any further major attacks at Verdun while the French mounted major counterattacks during the rest of the year, retaking Forts Douaumont and Vaux in October and November respectively.

By the time the battle finally ended on December 18th, in the midst of a worsening winter, the German army had gained a few kilometres along a 35km front. Both armies had been dreadfully damaged. Final casualty figures vary but it is estimated that the French lost more than 550,000 casualties while the Germans lost 434,000, with about half of this number being killed. In a real sense, there had been no strategic or tactical gains on either side and for the remainder of the year, the German army reverted to a defensive posture on the Western Front. From a French perspective, General Robert Nivelle, having retaken Forts Douaumont and Vaux, emerged as a national hero and was made commander-in-chief. This was to have long-term negative consequences as Nivelle’s plans for a decisive offensive in 1917 would end in disaster.

The fact that the Germans had attacked the French in February put the other Allies under pressure to meet the agreement reached at the Chantilly Conference – to mount an offensive if any of the Allied nations were attacked. Joffre put his fellow Allied commanders under pressure to come to France’s aid and this resulted in the various offensives that unfolded over the course of the year as the Russians, British and Italians mounted offensives to take the pressure off Verdun.

The first to respond were the Italians, who began the Fifth Battle of the Isonzo on March 9th. This attack would be followed by four more offensives on the Isonzo during 1916, the last one taking place in November. The Italian generalissimo, General Luigi Cadorna, was, without doubt, one of the worst generals of the war. The Isonzo offensives were characterised by massed infantry attacks over difficult terrain, poor artillery support and high casualties. They also brought no strategic gains.

On May 14th, the Austro-Hungarian army began an offensive against the Italians; the Trentino Offensive. This would run on until early June, putting the Italians under further pressure. Faced with near-collapse along their front, the Italians in turn begged their Russian and British allies to launch offensives to take the pressure off them.

The Russian Northern Army Group of 350,000 men under General Alexei Kuropatkin launched a major offensive on March 18th in the direction of Lake Naroch (in modern-day Lithuania). They were faced by about 75,000 German defenders. Despite the superiority in numbers and the fact that the attack was preceded by the largest artillery barrage yet seen on the Eastern Front, the offensive bogged down. Pre-offensive reconnaissance had been poor and the attack was poorly-timed, coinciding with the start of the spring thaw. The battlefield became a mudbath and inadequate training led to Russian troops bunching up, making them targets for German machine gun crews. By the end of the battle, the Russians had lost more than 100,000 men and had failed to draw German forces from the Western Front or, indeed, to aid the flagging Italians.

Due to the continued difficulties of both the French and the Italians, the Russians mounted a further major offensive on June 4th. This is commonly-known as the “Brusilov Offensive” after the commanding general, Alexei Brusilov but was also known in Russia as the “June Advance”. It actually encompassed a series of offensives that ran until September in the Galicia region.

Brusilov’s Southern Army Group of more than 600,000 men enjoyed considerable success, over-running about 25,000sq km of enemy territory in a series of simultaneous attacks along the front. Artillery preparation was more focused and effective than previously and the Austrian-Hungarian Fourth and Seventh Army were effectively demolished, with more than 1.5 million casualties of which about 400,000 were taken prisoner. By WW1 standards, Brusilov’s success was nothing short of spectacular and came near to taking Austro-Hungary out of the war. Consolidating initial successes proved impossible as the later phases of the operation overstretched the Russian logistical system. While this Russian success encouraged Romania to enter the war on the Allied side, this also created no long-term strategic opportunities.

It was against this backdrop of wider offensive action that the plan for the Somme offensive was developed. Planning for a major Allied offensive in this sector had begun in late 1915 and it was originally intended to be a major French effort with British support. Ironically, Joffre conceived it as an attritional battle in the hope of destroying German reserves and also gaining some territory.

The onslaught at Verdun resulted in it becoming a predominantly British offensive with only one French army, the Sixth, taking part in the initial phase. In retrospect, the objectives were wildly optimistic and planning made little allowances for the actual operational realities on the Western Front at that time.

Haig, who would have preferred to attack in Flanders, completed his preparations slowly, much to the irritation of Joffre. The final force assembled consisted of more than 750,000 men supported by about 3,000 British and French artillery pieces. However, the majority of British troops were wartime volunteers formed up in Kitchener or “Pals” battalions. They had little military experience and were totally unprepared for what would subsequently unfold.

Initially planned for August 1st, French pressure resulted in the attack opening a month earlier on July 1st. Despite the rushed nature of the final preparations, Haig and his staff felt confident that the eight-day preliminary bombardment would destroy German defences and, indeed, the majority of German troops.

Taking place across a 30km front between Amiens and Péronne, the northern wing of General Rawlinson’s Fourth Army was expected to break through and exploit while troops in the southern wing would move forward, heavily-laden with entrenching supplies, to consolidate their gains. Cavalry was massed with the intention of exploiting the eventual breakthrough.

Not without reason, the Somme has become a metaphor for military failure and incompetence. The preliminary barrage failed to break the German wire and adequate German defenders survived in heavy concrete bunkers to repel the British attack. The British troops who advanced at 7.30am on July 1st were met with a hail of fire. By the end of the day, they had suffered about 58,000 casualties, of which more than 19,000 had been killed. A small number of divisions, including the 36th Ulster Division, made some initial success. The French attack also made good progress but all along the line, the attack faltered.

Despite the high casualties, Haig persisted in this offensive over the coming weeks and various methods were used to get this stalled operation moving. A night attack on July 13th-14th made limited gains and Australian troops captured Pozières, seen as a key location, on July 23rd. The French Tenth Army joined the attack in September, a sign that pressure had eased at Verdun and, indeed, that the Germans had moved some troops to defend against attacks on the Somme. On September 15th, tanks were sued for the first time, creating short-lived panic among German troops.

Yet overall, the history of the Battle of the Somme makes for grim reading as Haig persisted in attacks on secondary objectives throughout the months that followed. These included operations in September against German strongholds at Guillemont and Ginchy, which involved the 16th Irish Division.

Haig is often criticised for continuing with the Somme offensive but it can also be shown that he was under considerable political pressure to continue the operation in light of French difficulties at Verdun. The offensive was finally called off on November 18th. By that time, the British had suffered 420,000 casualties while the French had sustained 200,000. German casualties are estimated at about 500,000. At the end of the offensive, the maximum depth to which the Allies had advanced was 12km, with no strategic advantage.

Among Allied politicians and generals there was a faction referred to as “the Easterners”, who advocated for operations on other fronts in order to take Turkey or Bulgaria out of the war. It was thought that the Salonika operation, based at modern-day Thessaloniki in Macedonia, offered such an opportunity. While Greece did not actually declare war on the Central Powers until June 1917, their army was mobilised due to perceived threats from Bulgaria and Turkey and also to provide some support to Serbia. In October 1915, the first contingent of French and British troops arrived in Salonika and the operation would be expanded to include four French and one British division.

This force included the 10th Irish Division, which was transferred from the Gallipoli front. The French commander, General Maurice Sarrail, initially found himself on the defensive and had to fortify his positions around Salonika, using a complex defensive zone. Having decided to maintain and expand the operation at the Chantilly Conference earlier in the year, Sarrail’s force was increased to more than 160,000 troops by January 1916.

Due to the complicated operational and political backdrop, they remained largely on the defensive, earning them the derisory nickname of “the gardeners of Salonika”. Planned offensive actions were delayed and although Monastir was captured in November, further major actions were postponed until 1917.

The Salonika force would later number more than 600,000 troops, including Italian and Russian formations and, in that sense, it was a truly Allied operation. The campaign was also a notoriously unhealthy one with more than 450,000 cases of malaria among the troops by 1918. As a means of occupying Bulgarian forces, it was a success but hopes that the operation would provide a knock-out blow to Bulgaria were to prove optimistic.

Alongside these major operations there was further military activity in the Middle East and also Africa. Yet, as both the Somme and the Verdun battles wound down in the winter of 1916, neither side had forced a decisive victory. For the Allies, so much had been driven by the agreements reached at Chantilly earlier in the year. The German attack at Verdun had resulted in a chain reaction of offensive action in an effort to dissipate German efforts or leave the Central Powers operationally over-stretched.

However, despite some initial success with the Brusilov Offensive, battlefield conditions on all fronts made a decisive breakthrough impossible. As the year drew to a close, the hopes of securing a strategic advantage remained unrealised. A series of costly offensives may eventually have relieved the pressure at Verdun but they had brought the end of the war no closer.

Allied leaders had to meet in late 1916 to decide on plans for the coming year. There was another military conference at Chantilly in November 1916, followed by an Anglo-French conference in London in December. Rather depressingly, the assembled politicians and generals drew up essentially the same plan that they had agreed upon 12 months previously.

The new French commander-in-chief, General Nivelle, planned for a war-winning offensive on the Western Front and there would be supporting attacks in Italy and Russia. Ultimately, none of this activity would result in Allied victory. By the end of 1917, Russia was effectively out of the war and all of the Allied nations were experiencing political upheaval and public discontent as the war dragged on and the losses mounted still higher. Peace movements on all sides pressed for an end to the war in 1917.

But peace, without victory, was simply not an option for any of the belligerent powers. The fact that political and military leaders on both sides convinced their populations of the rightness of such a mindset ensured that the war continued. Dr David Murphy lectures in military history and strategic studies at Maynooth University. His most recent book is Breaking Point of the French Army: the Nivelle Offensive of 1917 (Pen & Sword, 2015)