On November 2, 2004, the film-maker Theo van Gogh was shot dead in broad daylight the centre of Amsterdam by a 26-year-old Dutch-born Muslim.
Van Gogh, a descendant of the artist Vincent van Gogh, was then stabbed and a knife left pinning a note to his body.
It accused Ayaan Hirsi Ali, a Somali-born woman politician who calls herself “an ex-Muslim”, of being harshly critical of Islam.
Police said van Gogh’s murder had been sparked by a controversial documentary called Submission he had made with Hirsi Ali earlier in the year.
The provocative film, broadcast on national television, featured a naked woman with verses from the Quran, which Muslims believe is the word of God, projected on to her back, with a commentary composed of the testimonies of abused Muslim women.
Ayaan Hirsi Ali, 34 at the time, had to be protected after the attack by special police bodyguards.
She later moved to the USA, saying she felt “very much afraid” in the Netherlands, and is the author of several best-selling anti-Islam books the most recent of which, Heretic: Why Islam Needs a Reformation Now, was published in 2015.
Reporting from Amsterdam for The Observer, Jason Burke, himself the author of a much-acclaimed book Al-Qaeda: The True Story of Radical Islam, said the “implications of the murder go beyond the Netherlands”, and had given rise to questions about “how to handle the tensions between freedom of speech and the impact of saying certain things”.
One of the cards left at the scene of the shooting said: “Rest in peace, Theo, freedom fighter for free speech”.
Eleven years later, questions about how to handle the tensions between free speech and the impact of saying certain things would again become centre stage, this time in Paris.
Shortly before noon on January 7, 2015, two gunmen, two brothers, forced their way into the offices of the French satirical weekly magazine Charlie Hebdo, and, armed with rifles and other weapons, killed 12 staff members and injured 11 others.
The reason for the killings was the offence caused by the magazine’s portrayal of the Prophet Mohammed.
While there was widespread condemnation of the attack as an assault on freedom of speech, the Charlie Hebdo killings also sparked a debate about how we balance a commitment to free speech with sensitivity to causing offence to others.
Speaking after the Paris attacks, German chancellor Angela Merkel strongly defended the need for free speech: “This is an attack against the values we all hold dear, values by which we stand, values of freedom of the press, freedom in general and the dignity of man”.
But the debate also gave rise to concerns that offensive speech might contribute to a climate where discrimination and even violence might be fostered.
And, anyway, where is the line to be drawn between “offensive speech” and “hate speech”?
Do people have the right to say whatever they want, short of inciting violence, however offensive others may find their words?
Long before the controversies caused by the killings in Amsterdam and Paris, novelist Salman Rushdie found himself at the receiving end of a fatwa (a death sentence), issued by Iran’s supreme leader Ayatollah Khomeini.
It happened in February 1989, and followed the publication of Rushdie’s 1988 book Satanic Verses, a book considered deeply offensive throughout the Muslin world.
Because of this threat, Rushdie had to spend years in hiding.
Speaking in the aftermath of the long-drawn out controversy, Rushdie said: “Nobody has the right not to be offended — that right doesn’t exist in any declaration I have ever read.
"If you are offended it is your problem, and frankly lots of things offend lots of people.
“I can walk into a bookshop and point out a number of books that I find very unattractive in what they say. But it doesn’t occur to me to burn the bookshop down.”
Rushdie’s comments, and the controversies that would follow later arising from the killings in Amsterdam and Paris, are very pertinent to and provide a context for the controversy brewing in Australian sporting circles (with far wider ramifications) following the recent sacking of the Australian professional rugby player Israel Folau.
This move, ending his lucrative contract, could also see him blocked from the Australian squad for the rugby world cup in Japan later in the year.
On May 16, Raelene Castle, the chief executive of Rugby Australia (the equivalent of the IRFU) announced that Folau’s A$4m (€2.5m) contract had been terminated after an independent panel found he committed a high-level breach of the code of conduct by posting religiously-inspired, anti-gay, comments on social media.
Rugby Australia stated that while Folau was entitled to his religious beliefs, he had to express them more “respectfully”.
Folau, who is 30, won 73 caps with Australia.
The chairman of Rugby Australia, Cameron Clyne, denied that an attempt was being made to silence players over their beliefs.
“We’ve made it very clear to the players they are not being silenced. They are absolutely free to express their views on their faith and other matters, but the threshold is those views, or views on any other matter, cannot cause offence.”
This, however, is the crux. In his book Free Speech in an Open Society, Rodney Smolla, professor of law at the College of William and Mary in the USA, emphasises the need to “tolerate intolerance” in a truly open society.
Punishing someone for expressing views that others may find offensive, obnoxious or insensitive may well come to be seen as a violation of that person’s right to freedom of speech or the related right to religious freedom.
The principles at stake here transcend not just rugby but all sport.
The Enlightenment thinker Voltaire (1694-1778) is usually associated with the statement “I disapprove of what you say, but I will defend to the death your right to say it”.
For Folau the issue is not just about saving a multimillion-dollar contract, but a crusade for the right to express his religious beliefs without discrimination.
Folau believes he has a “duty to share God’s word”. He reignited the controversy on April 10 when he posted that hell awaited homosexuals and an array of other sinners if they did not repent.
Some Australian commentators are already predicting that the Folau case will end up in the Supreme Court, where it will almost certainly be seen as a test case, and one that could set a precedent with wide-ranging implications.
“The Israel Folau dispute is set to become a test case for religious freedom in Australia with ramifications that will potentially go beyond the confines of rugby,” according to Bret Harris of The Sydney Morning Herald.
Some have argued that Folau’s method of evangelising via social media is abhorrent and devoid of sensitivity, but others contend that however loathsome or offensive some people consider the manifestation of Folau’s religious beliefs to be, he has the right to express them.
What seems to be agreed is that a protracted legal battle in the courts is now looking increasingly likely.