The seventeen hymns that form the oldest and most sacred portion of the Avesta — and the only texts in the Zoroastrian canon accepted as Zoroaster's own compositions. Written in a form of Old Avestan so archaic that even ancient Zoroastrian priests found them difficult, the Gathas are simultaneously liturgical poetry and philosophical theology: they proclaim the existence of one supreme deity (Ahura Mazda), describe the cosmic struggle between truth (Asha) and falsehood (Druj), and call on human beings to choose through their own free will which side they stand on. The Gathas are the founding document of one of the world's oldest monotheistic traditions and a direct influence on Jewish, Christian, and Islamic eschatology.
