Festivals are periods of time, cut out from daily life, during which a group performs activities that are most often thought of as communications with the superhuman world. Festival names in Greece and Rome often express this close connection with a divinity, a hero, or a human founder, or they refer to a ritual activity that is characteristic for a festival. The basic ritual elements that underlie a specific festival scenario are similar in both cultures (as well as in other cultures of the ancient Mediterranean world): processions, sacrifices with ensuing banquets, and athletic and musical contests are most common and exist already in the festival descriptions in Homer, such as the New Moon festival on Ithaca in the Odyssey. Common festivals founded and expressed group identity, first and foremost on the city level, but also for smaller and larger groups, from the family and clan group to the tribe or the community of all Hellenes. Greek and Roman festivals were so similar in their basic forms that, during the Imperial epoch, cities in the eastern part of the Empire adopted Roman festivals despite the fact that Greek cities followed a lunar calendar, whereas Rome early on had introduced a luni-solar system. The one festival type absent from the Roman world, at least during the Republican epoch, was the mystery ritual that, typically through a one-time initiation ritual, founded groups that transcended a single city, as well as the limits of gender and social status.
During the Imperial epoch, both Rome and the cities of Greece continued their traditional festivals, but also developed their festival calendars in new directions, continuing and exploring innovations that had occurred already in Hellenistic times. An early development was ruler cult, developed in the Greek cities during Hellenistic times and adopted for the cult of Roman emperors, who exploited its potential to tie together a heterogeneous empire through shared cultic activities. The most important driving force was an understanding of divine power that was defined through its helpful manifestation and thus allowed the cult of outstandingly powerful humans. Wealthy citizens of Hellenistic cities also founded festivals in the memory of family members, and during the Imperial period, such foundations multiplied and gained in grandeur. The Imperial epoch also saw the extension of single festivals to events that lasted many days, if not an entire month and helped to shape the Christian festival calendar with its long festival periods.
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.