The world went to war in 1914 because of a lie, according to a new book about the teenage assassin who fired the fatal shot that sparked the conflict.
Writer Tim Butcher has traced the footsteps of Gavrilo Princip who shot Archduke Franz Ferdinand, the heir to the throne of the Austro-Hungarian Empire, dead in the streets of Sarajevo.
His death in 1914 saw Austria-Hungary declare war on Serbia which it said was behind the attack - a move that eventually drew Germany, France, Russia and Britain into the conflict, the First World War, that left millions dead.
Mr Butcher, who spent three years researching Princip and even uncovered his old school reports, said there is no evidence the Serbian government was behind it.
He said: "It was a claim made repeatedly by hawks in Vienna to justify an attack on Serbia, a claim that was accepted at the time by some historians and repeated even today by contemporary historians. But it is a claim not supported by evidence.
"Princip spent time in the Serbian capital before the assassination, and he met extremist nationalists there who helped arm him and smuggle him back to Sarajevo. But it does not follow these extremists were backed, authorised or even known about by the Serbian government.
"Vienna's declaration of war on Serbia as punishment for the Sarajevo assassination had about as much legitimacy as a declaration of war by Britain on Ireland as retaliation for Louis Mountbatten's murder in 1979 by Irish nationalists."
Mr Butcher, whose book The Trigger - Hunting The Assassin Who Brought The World To War comes out next month, said Princip's story was "twisted" and he could not " reasonably be accused of being a Serbian nationalist".
He argued that Princip actually wanted to create a country not unlike the Yugoslavia that emerged after the First World War, saying : " From the moment Austria-Hungary, in the face of clear evidence to the contrary, wilfully misconstrued Princip's motives in order to justify its attack on Serbia, distortion was inserted into the founding narrative of the First World War."
Princip, who was 19 at the time of the attack, was caught almost immediately and died in prison from tuberculosis in April 1918, just a few months before the end of the war.