How the First World War Began

The origins of the First World War are one of the most discussed phases of modern history. In this long read, we look at the reasons behind the war and the events that led to the great powers of Europe declaring war on one another.

The 1815 Congress of Vienna established what came to be known as the “Concert of Europe”. This settlement was intended by the European powers to keep the lid on the forms of nationalism that had caused the series of European wars between 1792 and 1815. However, whilst there were, indeed, less of the major European (and mainly French-led) wars, the Concert of Europe was less effective in the Balkans where the small new states of Serbia, Montenegro and Romania depended on the patronage the larger Russia and Austro Hungary for their survival.

Austro Hungary was an amalgam of eleven different ethnic groupings with, often conflicting interests, many of which included significant populations living outside of their “mother country.” For example, Austria was primarily populated with ethnic Germans. In 1908, Austro Hungary had annexed Bosnia Herzegovina. This action had alienated Russia who felt protective to the Slavic populations of the Balkans. In addition, due to the presence of Serbs and Croats who lived in Bosnia Herzegovina, the annexation led to calls for those people to be governed by Serbia, where Serbs and Croats formed the dominant political power. In 1912 and 1913, Serbia had fought two wars of expansion that had taken both territory and population from Austro Hungary and, in both cases, the Concert of Europe had failed to broker an agreement.

Archduke Franz Ferdinand, the heir to the Austro Hungarian throne, was acutely aware of the need for an alliance with another powerful regional power to buttress his empire. Romania was a good match, with an army that was significantly larger than Austro Hungary’s, however, there was a fly in the ointment where a continuing dispute over the Transylvanian region, where Magyrs ruled over ethnic Romanians, rumbled on. Rejecting any form of reform, the Magyrs were an immovable obstruction to resolving the issue and, as Franz Ferdinand strove to keep Austro Hungary together, were bound to be net losers in any concessions needed to placate other groups, most notably the Serbs, Bosnians and Croats. Widely seen as a reformer, Franz Ferdinand became a target for assassination as disaffected group believed that his assassination would prevent the implementation of the reforms that many feared.

Franz Ferdinand and family
Archduke Franz Ferdinand with his wife Sophie, Duchess of Hohenberg and their three children

In the absence of being able to broker an agreement with Romania and fearful of triggering an intervention from Russia in the event of a Balkan conflict, Ferdinand requested a guarantee of support from the Germans – this was not forthcoming. Casting about for alternatives to Romania, the next most likely option was Bulgaria. Able to exert pressure on Serbia via its shared border, it also was able to protect against any Russia advance; accordingly Austro Hungary began to woo this new potential bride. In order to help bring about the union, the Austro Hungary Foreign Minister, Franz von Matscheko committed his thoughts to a letter that made the case for the alliance to both Franz Ferdinand and to the Germans whose financial strength would be required to bankroll the alliance.

On June the 28th, the Archduke and his wife made a planned visit to Sarajevo. In the absence of any secrecy about the visit, a group of students, calling themselves the “Young Bosnians”, who were advocates of expansionist Greater Serbian principles, planned to assassinate the Archduke. Their assassination attempt, positioning seven assassins along the main route of the Archduke’s cavalcade, failed when most of the assassins lost their nerve and when a bomb thrown at the Archduke’s car rolled under another car. However, by one of those quirks of fate upon which history can turn, later on in the day, the Archduke’s car took a wrong turn and passed by one of the students. Gavrilo Princep took the opportunity presented to him and shot both the Archduke and his wife. They were pronounced dead just after 11am.

Princep, as an ethnic Bosnian coming from a Bosnian pressure group, drew suspicion onto the Serbians, as it was widely, and correctly, assumed that they had sponsored by the Serbian authorities. The Serbian Prime Minister, Pasic, caught between a strong and hawkish military, which had sponsored the Young Bosnians and the need to mollify international opinion failed to condemn the assassination strongly enough, leaving a suspicion that it had, indeed, been a Serbian plot.

Matscheko proposed to the ageing Emperor Frank Josef that it was time for a “final and fundamental reckoning with Serbia. This view concurred with that of the Austro Hungarian Chief of Staff, Franz Conrad von Hotzendorf. It was his belief that Serbia had to be neutralised as a threat and as soon as possible. Von Hotzendorf, a man of Clausewitzian beliefs, had been kept in check by Franz Ferdinand and Matscheko, but now found that his hawkish opinions were pushing at an open door. His desire for personal glory and belief that the odds on an Austro Hungarian victory against Serbia reduced the longer the potential war was postponed, led him to the conclusion that she would be better of fighting now rather than when Serbia was stronger.

Franz Conrad von Hotzendorf
Franz Conrad von Hotzendorf

Accordingly, the Austro Hungarian government rapidly developed a new policy position that a war with Serbia was both inevitable and preferable. However, any war against Serbia carried the massive risk of Russia intervention; it was this risk that the Austro Hungarians now sought to counter.

Conrad’s belief that Austro Hungary would struggle in any was grounded on the twin pillars of European military strength; manpower and firepower. In both these areas Austro Hungary lagged behind its local rivals and other Eurpoean powers, lacking front line troops, reserves and modern artillery in the quantities required. Austro Hungary found itself in a position where it was unable to rearm quickly enough for the new challenges of 1914. Put simple, Austro Hungary was incapable of fighting a war in the Balkans whilst also defending itself from other powers that might get involved.

The answer to this weakness was a military alliance with Germany. An alliance would protect Austro Hungary from Russia and to lend weight to her efforts to bring Bulgaria into an alliance. Kaiser Wilhelm, fired up with anger over the loss of his friend Franz Ferdinand, called his ministers together and rapidly agreed to support Austro Hungary in the event of Russia’s intervention in the Balkans. What Austro Hungary decided to do with Serbia was very much left for her to decide. On the 6th of July, the German high command’s decision was communicated to the Austro Hungary, given her freedom of manoeuvre and a seemingly unlimited guarantee of support.

As Austro Hungary and Germany forged closer links, it is opportune to consider the other great European Alliance; the Triple Entente.

The Entente was made up from seemingly incompatible countries; Great Britain, France and Russia. Britain and France were traditional enemies, Russia was an autocratic monarchy in contrast to France’s republic and Britain and Russian interested often conflict in Asia due to the presence of the Britain’s Indian empire., it was hard to imagine them as instinctive bed fellows. However, these countries had, by 1914, made various bilateral agreements that bound them together.

The German high command looked at the apparent contradictions within the Entente and concluded that such a brittle alliance could and would be ruptured if placed under any kind of strain.

The Germans calculated that, in the event of a war breaking out between Austro Hungary and Serbia, either Russia would not fight because it was not ready to do so, or if it did, it would be ineffective. Crucially, Germany calculated that Russia would not be supported by France and Great Britain. German fears of growing Russia strength (she was already embarked on a major rearmament programme) meant that, like Austro Hungary, she had an incentive in pre-emptive war and therefore would not see a military outcome as a disaster, should that unlikely scenario play out of any crisis in the Balkans. Accordingly, Germany made assurances to support Austro Hungary, attempted to localise the crisis to Austro Hungary and Serbia and, whilst not expecting a fight, did not fear an encounter with Russia.

The German leaders reasoned that the Russians shouldn’t want a war because they were militarily unprepared and because politically there was no moral imperative to support Serbia; after all, Serbia had sponsored the assassinations. It therefore followed that, if Russia chose to go to war, they must be using the crisis as a pretence for military action and, in the face of such aggression, Germany would have no choice but to defend herself.

Within the Austro Hungarian government itself, opinion moved in favour of a strike against Serbia, overcoming Hungarian concerns rooted in internal ethnic considerations. On the 23rd of July, an ultimatum was delivered to the Serbian government demanding three main actions; that the Serbians round up terrorist groups in Serbia, that propaganda against the Austro Hungarians be ceased and that Austro Hungary should have representation on the panel investigating Archduke’s assassination. The Austro Hungarian ambassador didn’t expect Serbia to meet these demands and didn’t stick around for a response.

In fact, Serbia did make some concessions, but only insomuch as they didn’t threaten her sovereignty. Austro Hungary’s demand to intervene in the internal Serbian assassination investigation, however, was considered a step too far and was refused. At the same time, Serbia appealed to international opinion for support, citing the apparent concessions. However the Serbian Prime Minister was convinced that Austro Hungary was intending on a war.

Russia also expected war. The Russian Foreign Minister Sergey Sazanov suspected that Germany had decided on provoking a preventative war against Russia in order to neutralise the threat of Russia rearmament. Accordingly, on the 24th of July, Russia mobilised some of its military to defend against any attack from Germany. Serbia mobilised its forces on the 25th in readiness for the expiry of the Austro Hungarian ultimatum.

Thus was set in train, literally, for it was rail transport that drove the need for mobilisation, a sequence of moves that were played out as if in a chess game. The need to deploy forces to the borders by rail and the rigid logistics of the rail timetable meant that, in order to have forces in position to counter a threat, it was necessary to transport troops from their bases and muster points as quickly as possible. As troops movements looked the same for offensive and defensive purposes, no nation would allow its neighbours to mass troops along a border without preparing its own troops to counter any offence. It therefore proved impossible to break the cycle of mobilisation, with each subsequent move provoking a counter move. The small Balkan crisis was escalating out of control and once mobilisation orders were given, it was a clear indication that war was much more likely.

In reality, only Great Britain was exempt from the inexorable logic of mobilisation, protected as she was by the sea and the Royal Navy; she alone did not need to deploy a large continental army in a short time period to threatened borders. However, the fleet, having been massed for the annual review, was kept together by the Sea Lord Winston Churchill, as an act of readiness.

On the 25th of July, in the expectation that Austro Hungary was planning to go to war, Serbia mobilised its army. At the same time, Franz Josef ordered that Austro Hungary mobilise on the 28th in preparation for an attack on Serbia. Fearful of the escalating situation, the British Foreign Minister, Sir Edward Grey, proposed to the Germans that a peace conference of the Concert of Europe be called to try and avert war. Grey also made it clear that, should any conflict develop from a localised Austro Hungarian and Serbian affair, Britain would be unable to stand aside.

Kaiser Wilhelm, returning from his yachting holiday on the 27th of July, was dismayed to hear of the risk that Britain may get involve. Realising that his high command’s calculations may be mistaken, he attempted to stop the Austro Hungarians and start mediation. His assessment of the Serbian response to the ultimatum was that it was adequate and “this document does away with any need for war”. By this stage, however, Conrad was determined to go ahead with his war and the Kaiser’s Chancellor believed he could stop any conflict from spreading.

In parallel to these moves, the French and Russian governments reinforced their commitment to each other and the need to stand firm, while France tried to convince Britain that she was still committed to peace. By reassuring Britain of their desire for peace, the French hoped to pave the way for British support in the event of a war, which France herself was largely committed to. The agreements between Britain and France had deepened from a general understanding to a more strategic alliance under Sir Edward Grey, but Grey was adamant that Britain retained freedom to act independently. However, towards the end of July, he went as far as to commit, and then rapidly withdrew, an offer to help France in the event of her remaining neutral in any conflict; effectively offering to guarantee her neutrality. In tandem with this, he rejected a suggestion from the Germans that they leave mainland France alone but take her colonial territories.

On the 28th of July, Austro Hungary declared war on Serbia. The Austro Hungarian army shelled Serbian targets across their border and naval vessels in the Danube shelled Sarajevo itself. The Austro Hungarian plan was to focus on Serbia and not to worry about the threat from Russia at this stage, based on the faulty logic that Russia would take much longer to mobilise than in reality she required.

The logic of mobilisation affected Germany perhaps more than any other nation. Ever fearful of the spectre of a war on two fronts and with both France and Russia as immediate and powerful enemies, war planning was predicated on the expected mobilisation timing of the protagonists. It was anticipated that France would mobilise fastest, therefore the German plan called for a short sharp strike with the bulk of her forces to defeat the French. This action was to take about five weeks and would neutralise the threat to Germany’s western borders. Then the German army would board trains and deploy to the east to face Russia.

This plan was predicated on Russian forces failing to move against Germany in any strength during the early stages of the war, but it was acknowledged that it be would be prudent to encourage Austro Hungary to position of some of her forces in the Galicia region. It was reasoned that this would divert Russian focus from attacking Eastern Prussia. As such, Germany pressurised Austro Hungary not to focus solely on Serbia and to move its 2nd Army to Galicia.

This was easier said, or demanded, than done. As a result of this move, Austro Hungary ended up with diluted forces on both fronts as the structure of the Austro Hungarian rail network, meant that it could only really move armies in one direction at a time.

Having picked a war with Serbia, Austro Hungary was now forced to denude the Serbian front in order to deploy to the Galician front. The absence of troops on the Serbian front meant that offensive action was dangerous, however, this was precisely the action that political pressure demanded; after all, what was the point of picking a fight with someone if only to defend once the fight had started. The key problem was manpower. Serbia could field around 350,000 troops, many of whom had recent battle experience, whilst the Austro Hungarians could field around 290,000 men, who were generally of lower calibre. The Austro Hungarian commander, Oskar Potiorek, developed a plan that aimed to encircle firstly the Serbian forces and, ultimately, Serbia itself. However, depending as it did on manpower that was subsequently diverted to the eastern front, it was rapidly derailed.

On the 30th of July, Tsar Nicholas ordered that the complete mobilisation of the Russian military. He had been unwilling to take this step, aware that it carried a very real risk of escalation. However, the Tsar had been convinced by his foreign minister, M Sazanoff, that he could delay no longer. In response to this move and in an attempt to avoid fighting Russia, Germany sent one last ultimatum the following day demanding that she should “cease every war measure against us and Austro Hungary”. This demand was rejected by the Russians who were unwilling and unable to risk not having their troops in position.

On the 31st of July, Britain asked both France and Germany to guarantee Belgian neutrality. The major powers of Europe, including Prussia as predecessor state to Germany, had each guaranteed that Belgium was to be preserved as a permanent neutral state when they signed the Treaty of London in 1839. Belgium, despite this guarantee offered a tempting alternative to the heavily defended and, often fought over, Franco-German border, presenting a line of least resistance for both the Germans and the French if they wanted to strike at one another. It was this eventuality that the British sought to pre-empt by seeking assurances from the French and Germans that they would not use this option; only the French were to respond.

On the 1st of August Tsar Nicholas, conscious of the escalating situation and keen to avoid a war, appealed to the Kaiser to avoid bloodshed. Later on that day, however, Kaiser Wilhelm, determined to honour his commitments to Austro Hungary, commanded full mobilisation of the German army. This was the last chance for peace in the east and committed Germany to war with Russia, but first the exposed western front must be neutralised.

Efforts in the German camp were now focussed on the role of Britain and France. The German ambassador, Lichnowsky, sent a last minute message to Berlin in which he expressed his belief that he had been offered a British guarantee that France would remain neutral if Germany was willing to undertake not to attack. However, this offer was based on a misunderstanding between Lichnowsky and Sir Edward Grey and was never a real option, nevertheless, it excited the Kaiser as he clutched at the hope that he could save himself a two-front war. Wilhelm immediately ordered that the German army’s opening moves in the updated Schlieffen plan be halted to allow this late plan for peace in the West to develop. Moltke, however, was adamant that his forces could not possibly be transferred to fight Russia in the east when the plan committed them to first crushing France. He stressed that any deviation to the plan could leave German forces in disarray and still facing potential French aggression.

At 11pm on the 1st August German troops at Trier were ordered to begin their move over the border into Luxembourg (whose independence was also guaranteed under the Treaty of London) in order to take control of a strategic rail and telegraph junction.

As the troops move over the border, King George V attempted to intervene by sending a telegram to the Tsar, urging restraint, but like Sir Edward Grey’s final futile telegram to Berlin, it arrived too late. As these last diplomatic moves were playing themselves out, Germany, already committed to war, presented the Russian Minister for Foreign Affairs, Sazanoff, with a formal declaration of war. In an emotional meeting Sazanoff turned on the German ambassador and told him that “the curses of the nations will be upon you”. He continued, “you could have prevented the war by one word; you didn’t want to.” The German ambassador had to be helped from the room in tears.

On the 2nd of August, German troops crossed the border with France for the first time and a number of small skirmishes broke out. In Britain, the Royal Navy was issued with a full war mobilisation order.

At seven o-clock on the evening of the 2nd, the Germans issued an ultimatum to the Belgian government, demanding free and safe passage across Belgian territory; the deadline set for a response was just twelve hours. The Belgians refused the ultimatum, citing the guarantees of the Treaty of London in 1839 and resolved to defend their country.

Theobald von Bethmann-Hollweg
Theobald von Bethmann-Hollweg – The German Chancellor

With the expiration of the ultimatum to Belgium on August the 3rd, Germany declared war on France and sent troops across the Belgian border in order to prepare for an attack on the French from the north. In the Reichstag, the German Chancellor, Bethman Hollweg acknowledged that German troops were in Belgium, stating that “The wrong –I speak openly – that we are committing we will endeavour to make good as soon as our military goal is reached”.

In line with her treaty obligations Britain sent an ultimatum to Germany demanding that Belgian neutrality be respected. For those in the British government who wanted war against Germany, Belgium presented a fine “casus belli”, or justification for war, untarnished with ulterior motives. They were to get their wish and at 11pm on the 4th of August, Britain’s ultimatum expired and war was formally declared.

In little over a month, the great powers of Germany, France, Great Britain, Russia and AustroHungary had gone from peace to being at war with each other. They would remain at war for over four more years.

Tracking the progress of World War 1 day by day