Sanctuaries and ritual traditions commonly gained prestige through claims of antiquity; conversely, novelty was an accusation occasionally leveled against groups such as the Christians. Yet ritual geography and practices were, in practice, always liable to revision, and it is evident that certain gods, holy places, and rituals had precise historical origins. How was change introduced, managed, and understood in the ancient Mediterranean world? Several varieties of innovation can be differentiated: (1) Many city-states had defined procedures for introducing new gods and initiating new collective rituals: those procedures were often envisaged as involving the active participation of the gods, as instigators or approvers of change. As in all religious systems balances were to be struck between existing religious authority, wherever vested, and the prophets, priests, and others who gained from the change; (2) Another variety of innovation represented homeostatic reactions to other changes, such as the foundations of cities, disasters survived, the fall or rise of monarchies, and the like; (3) Potentially most disruptive were those innovations brought by migration and/or the transfer of ideas and rituals across the connected Mediterranean world. The spread of mystery religions, of astrology, and of new gods provide examples of this. Certain societies were more receptive than others to this kind of novelty. Religious innovations of the first two kinds were often assimilated into the loosely bounded ritual systems of antiquity, but other changes had a cumulative effect that changes the religious geography permanently.
Ancient Greek religion was a polytheistic religion without a book, church, creed, or a professional priestly class. Due to the extraordinarily rich regional varieties in cult, fragmentary evidence and conjectural interpretations of it, conflicting mythological accounts, and the span of time treated, not a single absolute statement can be made about any aspect of Greek religion and exceptions exist for every general rule stated here. Since Ancient Greeks perceived all aspects of nature as either divine or divinely controlled, and all aspects of individual and social life were thought to be subject to supernatural influence, paying proper respect to the gods and heroes was understood to be a fundamental necessity of life. Since no aspect of individual or social life was separate from “religion,” scholars refer to Ancient Greek religion as “embedded.”1 The closest Ancient Greek comes to the English word “religion” are the noun thrēskeia (“acts of religious worship, ritual, service of gods”) and the verb thrēskeuō (“to perform religious observances”). Basic components of religious worship were the construction and upkeep of divine precincts, statues, altars, and temples, the observance of festivals, performance of sacrifices, bloodless offerings and libations, prayer, hymning, and observance of ritual abstinences and purifications. The closest Greek equivalents to “belief” were eusebeia (“reverent piety,” “respect”) and pistis (“trust in others” or “faith”).2 Both words could qualify a relationship between humans, as well as a relationship between humans and a supernatural entity. Since the Ancient Greeks did not have authoritative or divinely sent books of revelation, there was no script telling them what or whom to believe in and outlining the reasons why. The Greeks did not have professional priests who preserved, interpreted, and disseminated religious norms.3 However, Greek literature is brimming with gods, and the stories about the gods, which they (and we) call “myths,” were not only in all their texts, but everywhere around them: depicted on their pottery, painted on their walls, chiseled on the stones of their buildings.4 In the public space, there were countless divine statues, and the temples, altars, sacred groves, and divine precincts were everywhere around them. Ancient Greeks learned about the gods by hearing, watching, and doing: by seeing their parents perform a sacrifice, by observing them as they prayed, swore an oath, or performed libations, by participating in processions, singing and dancing in the chorus, eating the sacrificial meat in the sanctuaries, and by drinking wine, the gift of Dionysus. Ancient Greeks had no immediate need for theodicy, for the gods could be either benevolent, or angry, and their benevolence was perceived as a sign that the worship the community offered was appropriate, whereas natural catastrophes, crippling defeats in wars, or epidemics were interpreted as manifestations of divine anger, provoked by some human error or misstep.5 Ancestral gods and heroes and the traditional way of worshipping them formed the cornerstone of Greek religiosity.