Zoroastrianism was founded between 1400 and 1000 BC by Zoroaster, whose Persian name was Zarathustra (see Thus Spake Zarathustra by Friedrich Nietzsche). This religion believes in the one divine spirit of Ahura Mazda, who will judge all souls at the end. Zoroastrianism views life on earth as a constant struggle between good and evil spirits, personified by Spenta Mainyu and Angra Mainyu, respectively. Ahura Mazda judges each individual sooul on how well he or she has fought in this battle. Naturally, the ethical distinnction between good and evil carries much significance in Zoroastrianism, as one must be able to distinguish between the good and the evil in order to fight the battle justly. Good thoughts, good words, annd good deeds are strongly emphesized. A collection of Ahura Mazda's hymns are gathered in the sacred Avesta.