AVESTA. Only a small part of the Avesta (MPers., Abastāg; the name probably means "the Injunction [of Zarathushtra]"), the collection of sacred books of Zoroastrianism, has come down to us: about three-quarters of the original texts, whose codification dates to the Sasanid period (third to seventh centuries CE), have been lost. The oldest extant manuscript is from the thirteenth century.

The oral tradition that has permitted the transmission of the texts is therefore very long, especially since significant portions of the Avesta go as far back as the first years of the first millennium BCE. This fact, together with the problems connected with the writing system employed (derived from the Pahlavi alphabet, of Aramaic origin) and with the manuscript tradition, means that the study of the Avesta is philologically among the most difficult and complex.

The selection of texts that has survived—first published by their discoverer...