Zarathushtra was an ancient prophet. He lived in Iran. Zoroaster of English language is same as Zarathushtra. He founded a religion named Zoroastrianism. This religion has a long history. It was the national religion of Sassanian Empire of ancient Iran. In Persian language, the name takes the form of Zartosht.
Most of the scholars agree that Zoroaster was a real person who lived long back. No one is certain about the time when he lived. Estimates tell that he lived about 3200 years before, around 1200 BC. Some other estimates tell that Zarathushtra may have lived anywhere between the 18th century BC and the 6th century BC.