Ancient Greek, encompassing the Archaic and Classical periods roughly from the eighth through fourth centuries BCE, belongs to the Hellenic branch of the Indo-European language family and existed as a set of related regional dialects, including Attic, Ionic, Doric and Aeolic, before Athenian Attic Greek became the prestige literary standard during the Classical period's flourishing of philosophy, drama and historiography.
Ancient Greek is the original language of the Homeric epics, the Iliad and the Odyssey, foundational texts for understanding archaic Greek religion and its pantheon of Olympian gods, and of the Homeric Hymns, shorter poems addressed to individual deities that served important cultic and liturgical functions in ancient Greek worship at sanctuaries across the Greek world. The language also carries the surviving fragments and complete works of Greek tragedy and philosophy that directly addressed religious and theological questions, including Hesiod's Theogony, which systematized Greek mythology's divine genealogy, and the philosophical writings of Plato and Aristotle, whose treatment of the soul, the divine and cosmic order profoundly shaped later Christian, Islamic and Jewish theology once translated and absorbed into those traditions centuries later.