The Islamic State has released a video, purportedly showing Moath al-Kasasbeh, the Jordanian pilot captured in December, being burned alive. The Jordanian government had pleaded with IS to release the hostage in exchange for a captured terrorist.
It has influenced Star Wars and Game of Thrones – and characters as diverse as Voltaire, Nietzsche and Freddie Mercury have cited it as an inspiration. So what is Zoroastrianism? Joobin Bekhrad finds out.