The Theogony (Greek: Θεογονία, Theogonía, the birth of the gods) is a poem by Hesiod. It was written in the 8th or 7th century BC, and uses the same dialect of Ancient Greek as Homer. This dialect is known as Epic dialect today. With the exception of the Illiad and the Odyssey, the Theogony is the oldest known source of Greek mythology.