Zoroastrianism is an Iranian religion created by Zoroaster, who lived in eastern ancient Iran around 1000 BC. Other names for Zoroastrianism are Mazdaism and Parsiism. It is the ancestral religion of the Persians.
Zoroastrianism is also dualist. Zoroastrians believe Ahura Mazda created the good spirits (Spenta Mainyu), and Angra Mainyu the demons. Zoroastrians believe people are free to choose between good and bad. Choosing good will lead to happiness, and choosing bad will lead to unhappiness. So it is the best to choose good. Therefore, the motto of the religion is "Good Thoughts, Good Words, Good Deeds".
Zoroastrianism was the state religion of Persia starting in the 6th century BC, including the Sassanid dynasty. In the 7th century AD, Persia was conquered by Islamic Arabs, and most Persians became Muslim. There is no boy circumcision in Zoroastrianism.
Nowadays, there are about 2.6 million Zoroastrians in the world. Most of them live in Iran, Pakistan or India, where there called Parsi. In Pakistan and India, they are called Parsis. Many Zoroastrians now live in the United States. Zoroastrian Fire Temples include one in Yazd City in Iran.