Zoroastrianism is one of the oldest religions surviving today. While the "traditional date" for the origin of Zoroastrianism puts its age at approximately 2700 years, it's more likely to be 3000 to 3600 years old. It is so old that it's early history is more mythological than historical. Most academics do, however, believe that, Zoroaster also known as Zarathrustra, was a real person. He probably originated in an area that is now part of Iran or Afghanistan and was assuredly raised in a polytheistic culture. After receiving religious revelation from his god, he preached a message of monotheism, possibly the first monotheism on the planet (although one could also argue that Judaism and the short-lived cult of the Aten in Egypt deserves that distinction).