No one knows the exact size of the Yazidi population. Estimates range from tens of thousands to 500,000 or more. Over centuries, they have been the target of violence and purges, including during the Ottoman Empire, and have survived as a close-knit community that does not proselytize.
Much confusion surrounds their beliefs, but scholars say Yazidi teachings are a mix of several traditions, borrowing from Christianity and Islam, and including some practices resembling ancient traditions in Persia.
The Yazidi believe that a supreme being created the world but does not rule it. Instead, his will is carried out by seven angels, chief among them the Peacock Angel, known as Malak Taus. Yazidis believe continual rebirth leads to purification, and therefore the sect does not believe in hell. The tomb of Sheikh Adi, in the town of Lalesh north of Mosul, Iraq, is a Yazidi shrine and pilgrimage site.
Yazidis pray to Malak Taus, who is also known as the Fallen Angel. But unlike fallen angels in some Christian traditions, who are banished from heaven, the Peacock Angel was redeemed.
Still, the Peacock Angel is also known to Yazidis as "shaytan," which is the Arabic word Muslims use for the devil. This is the source of the belief among many Iraqi Muslims that Yazidis worship the devil, and it is among the reasons Yazidis are being targeted by the militant Islamic State group.