Ancient Greek religion refers to the religious beliefs, practices, and philosophy of the ancient Hellenes. Though distinct from ancient Greek mythology, Greek religion incorporated many of these traditional stories and myths into its religious forms. Even though Greek religious origins reach back to the earliest eras, the form that is understood today developed from the 8th century B.C.E. to the 4th century C.E. and resulted from the integration of the practices and beliefs of Greek-speaking peoples from the north of Greece with those of the indigenous peoples called "Pelasgi." As recorded by the poems of Homer (c. 9th century B.C.E.), ancient Greek religion consisted of a pantheon of gods and goddesses (including Zeus, Hera, Aphrodite, Poseidon, and Ares), most of whom had anthropomorphic qualities. The gods also represented the various aspects of the universe: the earth, sea, fire, mountains, sun, rivers, etc. Devotion to the gods was seen as an essential part of participating in Greek society, and many religious practices were based on the cults of the different gods. Ancient Greek religion did not have any sacred texts and the role of the priests was simply to look after the cults, but they were not considered clergy. Participation in Greek religion consisted of believing in the gods and performing rituals and sacrifices to honor and appease the gods.