Yazidism: the forgotten religion facing extermination at the hands of Islamic State jihadists

It's an unfortunate truism that the world pays attention to largely forgotten communities only in their moments of greatest peril.

This week, the world has watched as tens of thousands of Yazidis - a mostly Kurdish-speaking people who practise a unique, syncretic faith - fled the advance through northern Iraq of Islamic State's jihadists, who have abducted and killed hundreds of this religious minority.

Ever since seizing Mosul, the forces of Islamic State have tried to transform their domain into an idealised caliphate - they have forced the conversion of religious minorities, destroyed the shrines of rival sects and butchered those they consider apostates.

This week, a Yazidi member of parliament in Baghdad appealed: "An entire religion is being exterminated from the face of the earth."

The Yazidis globally number about 700,000 people, but most - about half a million - live in Iraq's north. The city of Sinjar was their heartland. Now, it's in the possession of extremists.

The Yazidi faith is a mix of ancient religions. Its founder was an 11th-century Umayyad sheikh whose lineage connected him to the first great Islamic dynasty.