Tim Butcher: The wars over our sense of identity are still raging on

But it also shows the exact corner where a young assassin, a 19-year-old farmer’s son from the wild west of Bosnia, Gavrilo Princip, was standing outside a café opposite the end of the Latin Bridge, an ancient Ottoman structure spanning the river.

What Princip did at that street corner changed all our worlds. He shot dead the Archduke, the event transformed by a diplomatic-political multiplier into the casus belli for the Great War.

Much has been written about Princip over the past century, much of it wrong. Over three years of research I have sought to strip away the muddle and misrepresentation and build the clearest picture of the young killer.

And what strikes me is how the motivation that drove him a century ago remains charged today, not least in Ukraine.

Born in Bosnia, he was a citizen of Austria-Hungary, just as Adolf Hitler was. But citizenry was not enough when empires were crumbling. A higher calling was then at work — nationalism.

Just like Irish nationalist assassins then fighting against British rule, or later Jewish nationalists murdering enemies of Zionism or Indian nationalists driven to shoot Mahatma Gandhi, Princip was motivated by the same desire: self-rule for his people.

It is a pure enough motivation but if the 20th century taught us anything it is how potentially toxic the principle can be.

Ever since the 1914 assassination, Princip’s case has been dogged by self-rule’s central issue — defining who one’s “people” are. Ethnically, Princip was a Bosnian Serb, tainting him by association with extremist nationalist Serbs.

But I would argue the evidence shows his calling was to define himself as a Slav, seeking common cause with all local Slavs, be they Bosnian Croat, Bosnian Muslim or Bosnian Serb.

In some ways the difference is academic: however you define yourself there is, necessarily, a definition of people who are not the same as you. And that is where toxicity enters nationalism — the reductionism of barriers raised against others.

Through fascism that originated in Italy, ironically enough, with violent calls to reclaim Balkan land not far from Princip’s birthplace, it was Hitler who took the barriers to the worst degree, dehumanising those “outside” as vermin to be exterminated.

Princip knew nothing of this, a sorcerer’s apprentice playing with political fire that he could not control.

This is where the old Baedeker guide touches us today. Another of its maps shows Austria-Hungary reaching deep into land we now know as Ukraine. The border, as drawn more than 100 years ago, no longer holds, an arbitrary “line in the soil” reflecting land then swapped between emperors.

But today’s crisis in Ukraine turns on the same issue of nationalism that drove Princip: a group of people who define themselves in one way (Ukrainian) resentful of another who define themselves in another way (Russian).

Parallels between 1914 Bosnia and 2014 Ukraine are plainly ludicrous. The detail of today’s stand-off is different and the willingness from a century ago of powers to engage in continental war does not, thankfully, apply now.

But the central issue of nationalism, how we define ourselves and how we find or do not find common cause with our neighbours, remains as unresolved today as it was 100 years ago, when Princip took up his station on that street corner faithfully marked by Baedeker.

Tim Butcher’s The Trigger — Hunting the Assassin who Brought the World to War, is published by Chatto & Windus.