As the floodwaters subsided, the Ark drifted across northern Iraq. Finally, with a crunching jolt, it hit dry land. Its timbers had scraped the peak of a mountain range called Sinjar. Water began to pour in. Fortunately, a black serpent, its coils as thick as an arm, moved to plug the breach. The Ark did not sink. Noah, his family, and all the various animals on board survived to repopulate the earth. This story, so familiar, so strange, can be seen illustrated in a shady courtyard that also boasts, just for good measure, the very spot where Adam is claimed to have been fashioned from dust. Lalish, a magical compound of domes, towers and stairways, stands in a valley in Iraqi Kurdistan.

To the Yazidis, a religious minority whose population straddles both the Kurdish region of Iraq and, to the south, the plain of Nineveh and the peaks of Sinjar, it is quite simply the holiest place in the world. Certainly, there is nowhere else in the Middle East which so seamlessly or mysteriously fuses the many cultural traditions of the region. Like Zoroastrians, the Yazidis tend sacred fires; like Christians, they practise baptism; like Muslims, they practise yearly fasts and daily prayers. One shrine at Lalish commemorates a sheikh who was once, very possibly, the Babylonian god of the sun. The Yazidis are charged with the palpable trace elements of antiquity.

Yet what makes people different can also make them hated. This is a lesson we hardly need teaching — it was Europeans who incubated ancient prejudices to such a monstrous pitch that our continent came to witness, within living memory, the most genocidal crime in history; it was Europeans, in the wake of Kristallnacht and Auschwitz, who vowed most fervently: ‘Never again.’

The ambition to wipe out an entire people, though, did not die with the Nazis. On 3 August 2014, it came to Sinjar. Isis fighters who had just captured the vast Iraqi city of Mosul fanned out across the plain of Nineveh. The Yazidis were deliberately targeted for extermination. The men, and those women deemed too old to be auctioned off as concubines, were murdered. Girls were enslaved, sold, raped. Boys were abducted to be brainwashed and turned into killers for Isis.

Here is the closest comparison that the current carnage in the Middle East offers to the Nazi persecution of the Jews. If parallels with the second world war must be drawn, then it is the Yazidis, of all the miserable peoples of Iraq and Syria, who have suffered the most terrible holocaust.

Why, then, has the world turned such a blind eye to their genocide? In large part it is because, numbering only 600,000, they rank as a minority in the genuine sense of the word. There are no Yazidi politicians in the West to press their case, no Yazidi columnists to beat the drum on their behalf. In August 2014, as Isis were busy shooting and enslaving, the panjandrums of the western media were in hotels 600 miles away, covering an altogether more familiar conflict. How could the sufferings of a people most journalists had never heard of compete for global attention with the reassuringly familiar rhythms of an Israeli incursion into the Gaza Strip?

Only with the tear-choked appeal for help from the sole Yazidi MP in the Iraqi parliament did their voices at last start to be heard. Even then, though, western journalists found it impossible to cover the genocide on the ground. TV news anchors did not head from Israel to northern Iraq. This was entirely understandable. Unlike the rival combatants in Gaza, Isis had a habit of beheading westerners on YouTube. Any journalists who had sought to visit the front line in Sinjar would have been condemning themselves to a hideous and very public death. The Yazidi genocide was not televised. Now, with the defeat of Isis in northern Iraq, the full story of what happened back in that dreadful summer of 2014 is at last starting to emerge. Yazidis shot and thrown like refuse into pits; men and boys beheaded in front of their families; girls as young as eight subjected to gang rape; beatings; forced conversions; torture; slavery. In a camp I visited, a woman who had been raped for an entire year, then shot in the head when her owner grew tired of her, then finally sold back to her husband, lay curled in a foetal ball in a makeshift tent, rocking and moaning to herself.

Still, though, the horror of it all seems not to be cutting through. Perhaps we in the West cannot give it our full attention because we are too deadened by a sense of our own complicity in the miseries of Iraq, and by the complexities of it all. When I visited the summit of Mount Sinjar last year, I found examples of both. A great hulk of concrete marked where Saddam had stationed one of his Scud missile launchers in the first Gulf War; next to it, in tents massed around an ancient temple, was a camp of female and distractingly attractive Marxist guerrillas. The PKK, whose role in protecting Mount Sinjar is remembered with gratitude by many Yazidis, were stationed there in defence of their own (often brutally promoted) brand of revolutionary socialism. Just like their fellow Kurds in the armed forces of Iraqi Kurdistan, their aim all along has been to establish a permanent sphere of influence over Sinjar. To this goal, the longing of Yazidis for a secure and dignified autonomy has always been peripheral.

Now, with the liberation of Mosul by the Iraqi army, and the return of Shi’ite militias to the plain of Nineveh, fresh ingredients have been added to the mix of ambitions. No wonder, looking at this swirl of competing interests and remembering what happened the last time they stuck their hands into the Iraqi magimix, that western powers shrink from intervening. Yet we owe it to the Yazidis not to forget them. Even as the feuding of rival Kurdish and Arab factions stop refugees returning to their homes in Sinjar, the poisonous interpretation of Islamic scripture used to justify their genocide has not gone away. The ideologues of Isis have awakened ancient ghosts. In ad 830, so it is said, a caliph visited Harran, and ordered the city’s inhabitants to convert or die. Centuries later, an Ottoman cleric issued a fatwa urging Muslims to slaughter Yazidi men and take their women as slaves: ‘According to the principles of the four schools of law, it is the duty of all Muslims to kill them.’ Isis are saying nothing new.

The Yazidis themselves claim to have survived 72 persecutions over the centuries. If they are to survive the 73rd as a distinct and coherent people, and not be scattered for ever from their ancient homeland, they need the backing of the outside world. Just as Noah fashioned a mighty vessel capable of withstanding the Flood, the Yazidis now need an ark of their own; one secure enough to keep them safe, and bring them back to rest in Sinjar.

Tom Holland and Gareth Browne discuss the plight of the Yazidis on the Spectator Podcast.

Men and boys ­beheaded in front of their families; girls as young as eight subjected to gang rape

Spectator.co.uk/podcast Tom Holland and Gareth Browne on the plight of the Yazidis.