By Mark Corcoran

The conventional interpretation of what happened on a Sarajevo street on June 28, 1914, is relatively straightforward.

Archduke Franz Ferdinand, the heir presumptive to the throne of the Austro-Hungarian Empire, and his wife, Sophie, were both shot by a 19-year-old assassin, an ethnic Serb named Gavrilo Princip.

Princip was a member of a militant nationalist group that vowed to liberate the southern Slav peoples of Bosnia-Herzegovina from the foreign rule of the Austro-Hungarian Empire.

He was trained and armed by Serbia's intelligence service, although Serbia's government denied any prior knowledge of the plot.

Photo: Archduke Franz Ferdinand and his wife Sophie (in back of car) in Sarajevo before they were both assassinated (Imperial War Museum)

The Austro-Hungarians were convinced they had a political smoking gun, and the 'July Crisis' was born.

Strident, unrealistic diplomatic demands were made of Serbia and predictably rebuffed. On July 28, 1914, the Austro-Hungarian Empire declared war.

This precipitated a disastrous chain reaction across Europe. Within one month:

• Russia declared war on Austria-Hungary
• Germany declared war on the Russians and Serbs
• France declared war on both Germany and the Austro-Hungarians
• Britain declared war on the Germans

And with Britain at war, so too was her Empire. Australia swiftly pledged support, with opposition leader and future prime minister Andrew Fisher declaring: "Australians will stand beside our own to help and defend her to the last man and the last shilling."

Generations of history students have since been taught that the two bullets fired by Princip led to the deaths of tens of millions, as Europe descended into a four-year conflict, unprecedented in its industrial scale and ferocity.

The assassination is widely viewed as the immediate trigger for the war, but to what extent was this a conflict already waiting to happen?

One hundred years on from that fateful day in Sarajevo, historians are still analysing and debating the deeper causes of the conflict.

"The presumption that it was caused by the assassination of Franz Ferdinand is one of the great furphies of history" says historian Paul Ham, author of 1914: The Year The World Ended.

He told ABC Radio's Conversations program: "Austria used the war to its own ends. It was a case for making war on Serbia. The death of the archduke could have been handled in all manner of ways."

Historians argue that the underlying causes of the war were varied and complex.

Balkan nationalism, an arms race, muscular colonial empire-building, political paranoia, simmering historical vendettas and even a deadly-efficient rail network, all played a part in propelling Europe down the rails and into the abyss of war.

Scramble for Africa as united Germany looked to secure export markets

Photo: Four 'Askaris', or local soldiers, in German East Africa. (Bundesarchive, Wikimedia Commons)

In the late 19th century a newly unified Germany emerged as an industrial power in Europe, a new economic force that wanted a colonial empire.

"[Otto von] Bismarck [the first chancellor of a united Germany] didn't initially seek an empire, but he saw belatedly in the 1880s that this was electorally popular, and certainly Germany needed the export markets for its products," says Ham.

"So it then tried to aggressively wedge its way into the African scramble in the 1890s – and this was treated with dismay by France, Britain and Russia, who were the de-facto owners of the world."

After Kaiser Wilhelm II acceded to the throne as Emperor of Germany in 1888, he sacked Bismarck in 1890 and embarked on a more aggressive foreign policy.

"A deeply vulnerable, paranoid, rather sad individual", says Ham. Kaiser Wilhelm strengthened relations with Austria, but decided not to renew a treaty with Russia.

Fearing Germany's long-term intentions, in 1894 France and Russia formed an alliance.

Paranoia and hatred fuelled European arms race

Photo: Britain's HMS Dreadnought pictured in 1906. (Wikimedia)

In 1898, Germany began building a navy to challenge Britain's supremacy of the seas.

This alarmed the British, who started construction of a new, bigger class of battleships called dreadnoughts.

Germany launched its own dreadnought program, and the naval arms race was on.

Concerned by German intentions, the British formed strategic alliances with France and Russia. Kaiser Wilhelm stepped up the rhetoric.

"In 1908, he had a famous interview with the Daily Telegraph in London, where he proceeded to declare that the British were mad, mad, mad as march hares....and to declare that the German navy would crush the British navy in the naval race which was then at its peak," says Ham, who argues that Kaiser Wilhelm’s paranoia had an undercurrent of truth.

France fielded the largest army in Europe, while Russia was rapidly developing an even bigger military. Germany felt squeezed between two growing military powers, equipped with new weapons.

"He was right, Germany was being encircled. The Triple Entente, that is Russia, France and Britain, had the largest armies, had the most powerful navy, shared the largest empires the world had ever seen – which were being denied any access to Germany," Ham says.

Had France and Britain been prepared to accommodate or conciliate with Germany, Paul Ham believes there may have ultimately been a different outcome, a view not shared by some historians.

Other military technologies were being urgently developed that would enable the industrial-scale slaughter to come. New machine guns were being manufactured that would soon be used with devastating effect on the front lines, the Germans had developed a powerful type of heavy artillery capable of obliterating trenches and fortifications, and the British were mass producing a new type of highly accurate rifle.

"They all saw it coming. Military commanders knew what these guns and weapons could do," says Ham.

"This idea that they were somehow stupid, that they stumbled into war, accidently groped their way into war - that does a great disservice to their intelligence".

Fear, paranoia and historical hatreds all contributed to the momentum. While the Germans felt encircled, Ham argues that the French were driven by a “visceral sense of revenge...to punish Germany” for the loss of the territory of Alsace-Lorraine to the Germans following the Franco-Prussian War of 1870.

War By Timetable: did Europe's rail system make war easier?

Photo: German soldiers in a train carriage on their way to the front early in World War I (1914). Messages scrawled on the side of the car include 'Trip to Paris' and 'See you on the boulevard'. (Wikipedia)

"War by Timetable" was the provocative title of a 1969 book by one of the most acclaimed historians of the 20th century, AJP Taylor, who theorised that the cause of World War I could be traced back to an unexpectedly efficient transport system.

Taylor said none of the major powers actively sought a conflict prior to 1914, but depended on deterrence, through an ability to mobilise their armies faster than their rivals.

He argued that in the decade leading up to war, the generals of all the great powers had developed elaborate plans to move vast numbers of men by rail to confront any threat; a strategy intended to intimidate any potential aggressor while also serving as a useful extension of foreign policy.

The problem, according to Taylor, came following the 'July Crisis' of 1914, when the strategy, which was intended to prevent a war, had precisely the opposite effect.

All across Europe hundreds of trains and millions of soldiers were set in motion, swiftly and inexorably towards conflict.

Mass troop mobilisation had effectively become a declaration of war as politicians and diplomats were shunted aside by generals and station-masters.

"The First World War had begun - imposed on the statesmen of Europe by railway timetables. It was an unexpected climax to the railway age," wrote Taylor.

Germany accused of deliberate push for war

In 1961 German historian Professor Fritz Fischer created a sensation when he claimed Germany had secretly used the July 1914 crisis as a pretext to deliberately launch a pre-emptive war against both France and Russia, even if that risked conflict with Britain.

Fischer’s research was based on access to official documents held by both the West and East German governments, that had remained unopened since the end of World War I.

He challenged the long-held orthodoxy that the conflict had been triggered by a series of political and military blunders on all sides.

When the English language version of Fischer's work was first published in 1968, the New York Review of Books noted: "It is still possible to find people who will tell you that both World Wars were a tragic, avoidable mistake ... For these people, the appearance of Fritz Fischer’s book is a blow of almost lethal destructiveness."

Balkan powderkeg ready to blow as Ottoman power faded

Photo: Ottoman troops with a flag during the pre-World War I Balkan Wars (National Library of France/Wikipedia)

While European empires were rapidly extending their influence around the globe, the Ottoman Empire, dubbed "the sick man of Europe", was in terminal decline.

Four centuries of Ottoman rule over the empire's Balkan territories was increasingly challenged by the nationalist movements of Serbs, Greeks, Romanians, Bulgarians, Albanians and others.

These ethnic groups ultimately drove the Ottomans out of their European territories, and gained their independence after fighting each other and the Ottomans in the two Balkan Wars of 1912-13.

Meanwhile, in 1908, the Austro-Hungarians had formally annexed Bosnia-Herzegovina, which they had been occupying since 1878. The move outraged Russia and Serbia, two nations linked by their Slavic and Orthodox identity, who dreamed of Bosnia's inclusion in a new Balkan Slav state.

In the Bosnian capital Sarajevo, the stage was set for the assassination of Archduke Franz Ferdinand.

Australia played no part in the events leading up to the War, but having been committed to defend Britain to the last man and last shilling, Australians would be forced to live -  and die - with the consequences.

Some 330,000 Australians served overseas. Of those, 61,500 were killed and around 155,000 wounded.

Origins of World War I: How trains, technology and a teenage assassin helped pitch Europe into conflict - ABC News (Australian Broadcasting Corporation)