Greek religion, religious beliefs and practices of the ancient Hellenes. Greek religion is not the same as Greek mythology, which is concerned with traditional tales, though the two are closely interlinked. Curiously, for a people so religiously minded, the Greeks had no word for religion itself; the nearest terms were eusebeia (“piety”) and threskeia (“cult”).
Although its origins may be traced to the remotest eras, Greek religion in its developed form lasted more than a thousand years, from the time of Homer (probably 9th or 8th century bc) to the reign of the emperor Julian (4th century ad). During that period its influence spread as far west as Spain, east to the Indus River, and throughout the Mediterranean world. Its effect was most marked on the Romans, who identified their deities with those of the Greeks. Under Christianity, Greek heroes and even deities survived as saints, while the rival madonnas of southern European communities reflected the independence of local cults. The rediscovery of Greek literature during the Renaissance and, above all, the novel perfection of Classical sculpture produced a revolution in taste that had far-reaching effects on Christian religious art. The most striking characteristic of Greek religion was the belief in a multiplicity of anthropomorphic deities under one supreme god. Priests simply looked after cults; they did not constitute a clergy, and there were no sacred books.
The sole requirements for the Greeks were to believe that the gods existed and to perform ritual and sacrifice, through which the gods received their due. To deny the existence of a deity was to risk reprisals, from the deity or from other mortals. The list of avowed atheists is brief. But if a Greek went through the motions of piety, he risked little, since no attempt was made to enforce orthodoxy, a religious concept almost incomprehensible to the Greeks. The large corpus of myths concerned with gods, heroes, and rituals embodied the worldview of Greek religion and remains its legacy. (See Greek mythology.) It should be noted that the myths varied over time and that, within limits, a writer—e.g., a Greek tragedian—could alter a myth by changing not only the role played by the gods in it but also the evaluation of the gods’ actions.
From the later 6th century bc onward, myths and gods were subject to rational criticism on ethical or other grounds. In these circumstances it is easy to overlook the fact that most Greeks “believed” in their gods in roughly the modern sense of the term and that they prayed in a time of crisis not merely to the “relevant” deity but to any deity on whose aid they had established a claim by sacrifice. To this end, each Greek polis had a series of public festivals throughout the year that were intended to ensure the aid of all the gods who were thus honoured. They reminded the gods of services rendered and asked for a quid pro quo. Particularly during times of crises, the Greeks, like the Romans, were often willing to petition deities borrowed from other cultures.