- Proper noun. The prophet of the ancient Iranian religion Zoroastrianism.
- Proper noun. Pseudepigraphic name used by various Greek and Latin authors of late antiquity to lend their opinions weight.
- Proper noun. Ostensible source/founder of the "mysteries" of the Roman ''Mysteriae Mithrae'' ("Mysteries of Mithras", "Mithraic Mysteries"), an astrology-centric, middle-platonic mystery cult of the 1st-4th century Roman Empire whose adherents worshiped in "caves" (i.e. Mithraea) in imitation of "Zoroaster". (Porphyry, ''De Antro Nympharum'' 6).