The Name Zoroaster, Zarathushtra or Zarathustra

Zarathushtra (Zaraϑuštra) is the original name of the founder of the Zoroastrian (Zarathushtrian) religion as it is found in the Zoroastrian / Zarathushtrian scriptures, the Avesta. [ϑ=th, and š=sh]

The spelling Zarathustra (ustra instead of ushtra) is often associated with Friedrich Nietzsche's, book Also sprach Zarathustra: Ein Buch für Alle und Keinenin known to English speakers as Thus Spake Zarathustra.

Zoroaster is the Western / English version of the name derived from the Greek version Ζωροάστρης, transcribed in English with diacritics as Zōroastrēs. This version of the name is found in the 5th century BCE Hellenic works of Xanthus of Lydia's (mid 5th Cent. BCE) Lydiaca (Fragment 32) and in Plato's (429–347 BCE) First Alcibiades (122a1 - See our post, Alcibiades, Plato and Some Amazing Insights. Other Greek texts use a variety of forms such as Zoroastris, Zoroastrou, Zaratos, and Zoroastren when transcribed into plain English. (Also see our blog, Greek Perceptions of Zoroaster, Zoroastrianism & the Magi.)

Quoting the authority of Ctesias, Diodorus Siculus (1st cent. BCE) in his Library of History 1.94.2 written in the reign of Augustus, uses the name Zathraustes, a name closer to the original Avestan Zarathushtra than the more commonly used Greek version Zoroastres. In his account, Diodorus states that Zarathushtra/Zoroaster was an Arian/Aryan and a native of east Iran.

The name Zoroaster is prevalent in Western English texts since it is Greek (and now English) texts that were the primary European record of the individual, his religion and his philosophy.