Today marks the centenary of the assassination of the heir to the Austro-Hungarian empire and his wife, sparking the First World War and leading to the deaths of 14 million people.

Tensions among competing European powers were already simmering when the double assassination pushed the situation to a critical point. Austria, backed by Germany, declared war on Serbia a month later in response to the killings, and Serbia was supported by Russia and France.

Photo circa 1914 of Archduke Franz Ferdinand, his wife Sophie, and their children Maximilian, Ernst and Sophie. PA Archive / Press Association Images PA Archive / Press Association Images / Press Association Images

Archduke Franz Ferdinand and his wife Sophie were visiting the city shortly after Bosnia became part of the Austro-Hungarian empire when they were targeted by a Yugoslav group seeking separation from Austria.

After a failed assassination attempt by a co-conspirator earlier on the day of 28 June, Bosnian Serb Gavrilo Princip fired the fatal shots into the royals’s open-air carriage. (As this 2011 Smithsonian article shows, the issue of whether or not Princip was grabbing a quick sandwich at a nearby cafe when he saw an unexpected opportunity to strike the archduke is still contended among historians.)

Front page of London newspaper The Times on June 29, 1914, AP / Press Association Images AP / Press Association Images / Press Association Images

Nineteen-year-old Princip was quickly arrested for the killings, sentenced to a 20-year term, and died in custody from TB in April 1918.

In Sarajevo today, public opinion on the assassin’s actions remains divided along ethnic divisions.

Franz Ferdinand and Sophie lying in state in Vienna, 1914. PA Archive / Press Association Images PA Archive / Press Association Images / Press Association Images

“Gavrilo Princip will, just like the past 100 years, remain a hero for some and a terrorist to others,” said the head of the Sarajevo History Institute, Husnija Kamberovic told the AP. “It is a matter of feelings toward what he did, and not a matter of serious historical arguments.”

Christian Orthodox Serbs celebrate Princip as someone who saw Bosnia as part of the Serb national territory. The same idea inspired the Serbs in 1992 to fight the decision by Muslim Bosnians and Catholic Croats to declare the former republic of Bosnia independent when Serb-dominated Yugoslavia fell apart.

In Serb history books, the “great liberation act” of Princip and his comrades is described for over 20 pages.

Gavrilo Princip, the 19-year-old student who killed the Austrian Archduke Franz Ferdinand and his wife, Sophie in 1914. PA Archive / Press Association Images PA Archive / Press Association Images / Press Association Images

“They were heroes who were ready to sacrifice their own lives for freedom and liberation,” said Jovan Medosevic, a primary school history teacher in the Bosnian Serb town of Pale, near Sarajevo.

That’s exactly what makes Princip unpopular among Muslim Bosnians and Catholic Croats. In their official textbooks, Princip is mentioned in just one sentence as a member of a secret terrorist organization who “did not assassinate Franz Ferdinand to liberate Bosnia from the occupier, but wanted Bosnia to become a part of Kingdom of Serbia,” high school student Ermin Lazovic said.

June 28, 1914 photo depicting the arrest of a man previously identified as Gavrilo Princip. AP / Press Association Images AP / Press Association Images / Press Association Images

- Additional reporting by the AP