Religion in ancient Rome

All sacrifices and offerings required an accompanying prayer to be effective. Pliny the Elder declared that "a sacrifice without prayer is thought to be useless and not a proper consultation of the gods."[34] Prayer by itself, however, had independent power. The spoken word was thus the single most potent religious action, and knowledge of the correct verbal formulas the key to efficacy.[35] Accurate naming was vital for tapping into the desired powers of the deity invoked, hence the proliferation of cult epithets among Roman deities.[36] Public prayers (prex) were offered loudly and clearly by a priest on behalf of the community. Public religious ritual had to be enacted by specialists and professionals faultlessly; a mistake might require that the action, or even the entire festival, be repeated from the start.[37] The historian Livy reports an occasion when the presiding magistrate at the Latin festival forgot to include the "Roman people" among the list of beneficiaries in his prayer; the festival had to be started over.[38] Even private prayer by an individual was formulaic, a recitation rather than a personal expression, though selected by the individual for a particular purpose or occasion.[39]

Oaths—sworn for the purposes of business, clientage and service, patronage and protection, state office, treaty and loyalty—appealed to the witness and sanction of deities. Refusal to swear a lawful oath (sacramentum) and breaking a sworn oath carried much the same penalty: both repudiated the fundamental bonds between the human and divine.[36] A votum or vow was a promise made to a deity, usually an offer of sacrifices or a votive offering in exchange for benefits received.

Roman relief depicting a scene of sacrifice, with libations at a flaming altar and the victimarius carrying the sacrificial axe

In Latin, the word sacrificium means the performance of an act that renders something sacer, sacred. Sacrifice reinforced the powers and attributes of divine beings, and inclined them to render benefits in return (the principle of do ut des).

Offerings to household deities were part of daily life. Lares might be offered spelt wheat and grain-garlands, grapes and first fruits in due season, honey cakes and honeycombs, wine and incense,[40] food that fell to the floor during any family meal,[41] or at their Compitalia festival, honey-cakes and a pig on behalf of the community.[42] Their supposed underworld relatives, the malicious and vagrant Lemures, might be placated with midnight offerings of black beans and spring water.[43]

The most potent offering was animal sacrifice, typically of domesticated animals such as cattle, sheep and pigs. Each was the best specimen of its kind, cleansed, clad in sacrificial regalia and garlanded; the horns of oxen might be gilded. Sacrifice sought the harmonisation of the earthly and divine, so the victim must seem willing to offer its own life on behalf of the community; it must remain calm and be quickly and cleanly dispatched.[44]

Sacrifice to deities of the heavens (di superi, "gods above") was performed in daylight, and under the public gaze. Deities of the upper heavens required white, infertile victims of their own sex: Juno a white heifer (possibly a white cow); Jupiter a white, castrated ox (bos mas) for the annual oath-taking by the consuls. Di superi with strong connections to the earth, such as Mars, Janus, Neptune and various genii – including the Emperor's – were offered fertile victims. After the sacrifice, a banquet was held; in state cults, the images of honoured deities took pride of place on banqueting couches and by means of the sacrificial fire consumed their proper portion (exta, the innards). Rome's officials and priests reclined in order of precedence alongside and ate the meat; lesser citizens may have had to provide their own.[45]

Denarius issued under Augustus, with a bust of Venus on the obverse, and ritual implements on the reverse: clockwise from top right, the augur's staff (lituus), libation bowl (patera), tripod, and ladle (simpulum)

Chthonic gods such as Dis pater, the di inferi ("gods below"), and the collective shades of the departed (di Manes) were given dark, fertile victims in nighttime rituals. Animal sacrifice usually took the form of a holocaust or burnt offering, and there was no shared banquet, as "the living cannot share a meal with the dead".[46] Ceres and other underworld goddesses of fruitfulness were sometimes offered pregnant female animals; Tellus was given a pregnant cow at the Fordicidia festival. Color had a general symbolic value for sacrifices. Demigods and heroes, who belonged to the heavens and the underworld, were sometimes given black-and-white victims. Robigo (or Robigus) was given red dogs and libations of red wine at the Robigalia for the protection of crops from blight and red mildew.[45]

A sacrifice might be made in thanksgiving or as an expiation of a sacrilege or potential sacrilege (piaculum);[47] a piaculum might also be offered as a sort of advance payment; the Arval Brethren, for instance, offered a piaculum before entering their sacred grove with an iron implement, which was forbidden, as well as after.[48] The pig was a common victim for a piaculum.[49]

The same divine agencies who caused disease or harm also had the power to avert it, and so might be placated in advance. Divine consideration might be sought to avoid the inconvenient delays of a journey, or encounters with banditry, piracy and shipwreck, with due gratitude to be rendered on safe arrival or return. In times of great crisis, the Senate could decree collective public rites, in which Rome's citizens, including women and children, moved in procession from one temple to the next, supplicating the gods.[50]

Extraordinary circumstances called for extraordinary sacrifice: in one of the many crises of the Second Punic War, Jupiter Capitolinus was promised every animal born that spring (see ver sacrum), to be rendered after five more years of protection from Hannibal and his allies.[51] The "contract" with Jupiter is exceptionally detailed. All due care would be taken of the animals. If any died or were stolen before the scheduled sacrifice, they would count as already sacrificed, since they had already been consecrated. Normally, if the gods failed to keep their side of the bargain, the offered sacrifice would be withheld. In the imperial period, sacrifice was withheld following Trajan's death because the gods had not kept the Emperor safe for the stipulated period.[52] In Pompeii, the Genius of the living emperor was offered a bull: presumably a standard practise in Imperial cult, though minor offerings (incense and wine) were also made.[53]

The exta were the entrails of a sacrificed animal, comprising in Cicero's enumeration the gall bladder (fel), liver (iecur), heart (cor), and lungs (pulmones).[54] The exta were exposed for litatio (divine approval) as part of Roman liturgy, but were "read" in the context of the disciplina Etrusca. As a product of Roman sacrifice, the exta and blood are reserved for the gods, while the meat (viscera) is shared among human beings in a communal meal. The exta of bovine victims were usually stewed in a pot (olla or aula), while those of sheep or pigs were grilled on skewers. When the deity's portion was cooked, it was sprinkled with mola salsa (ritually prepared salted flour) and wine, then placed in the fire on the altar for the offering; the technical verb for this action was porricere.[55]

Human sacrifice in ancient Rome was rare but documented. After the Roman defeat at Cannae two Gauls and two Greeks were buried under the Forum Boarium, in a stone chamber "which had on a previous occasion [228 BC] also been polluted by human victims, a practice most repulsive to Roman feelings".[56] Livy avoids the word "sacrifice" in connection with this bloodless human life-offering; Plutarch does not. The rite was apparently repeated in 113 BC, preparatory to an invasion of Gaul. Its religious dimensions and purpose remain uncertain.[57]

In the early stages of the First Punic War (264 BC) the first known Roman gladiatorial munus was held, described as a funeral blood-rite to the manes of a Roman military aristocrat.[58] The gladiator munus was never explicitly acknowledged as a human sacrifice, probably because death was not its inevitable outcome or purpose. Even so, the gladiators swore their lives to the gods, and the combat was dedicated as an offering to the Di Manes or the revered souls of deceased human beings. The event was therefore a sacrificium in the strict sense of the term, and Christian writers later condemned it as human sacrifice.[59]

The small woollen dolls called Maniae, hung on the Compitalia shrines, were thought a symbolic replacement for child-sacrifice to Mania, as Mother of the Lares. The Junii took credit for its abolition by their ancestor L. Junius Brutus, traditionally Rome's Republican founder and first consul.[60] Political or military executions were sometimes conducted in such a way that they evoked human sacrifice, whether deliberately or in the perception of witnesses; Marcus Marius Gratidianus was a gruesome example.

Officially, human sacrifice was obnoxious "to the laws of gods and men". The practice was a mark of the barbarians, attributed to Rome's traditional enemies such as the Carthaginians and Gauls. Rome banned it on several occasions under extreme penalty. A law passed in 81 BC characterised human sacrifice as murder committed for magical purposes. Pliny saw the ending of human sacrifice conducted by the druids as a positive consequence of the conquest of Gaul and Britain. Despite an empire-wide ban under Hadrian, human sacrifice may have continued covertly in North Africa and elsewhere.[61]

Small bronze statues of gods for a lararium (1st to 3rd century AD, Vindobona)

The mos maiorum established the dynastic authority and obligations of the citizen-paterfamilias ("the father of the family" or the "owner of the family estate"). He had priestly duties to his lares, domestic penates, ancestral Genius and any other deities with whom he or his family held an interdependent relationship. His own dependents, who included his slaves and freedmen, owed cult to his Genius.[62][63]

Genius was the essential spirit and generative power – depicted as a serpent or as a perennial youth, often winged – within an individual and their clan (gens (pl. gentes). A paterfamilias could confer his name, a measure of his genius and a role in his household rites, obligations and honours upon those he fathered or adopted. His freed slaves owed him similar obligations.[64]

A pater familias was the senior priest of his household. He offered daily cult to his lares and penates, and to his di parentes/divi parentes at his domestic shrines and in the fires of the household hearth.[65] His wife (mater familias) was responsible for the household's cult to Vesta. In rural estates, bailiffs seem to have been responsible for at least some of the household shrines (lararia) and their deities. Household cults had state counterparts. In Vergil's Aeneid, Aeneas brought the Trojan cult of the lares and penates from Troy, along with the Palladium which was later installed in the temple of Vesta.[66]

Three flamines in their distinctive pointed headgear, grouped to the centre of a panel from the Ara Pacis

Rome had no separate priestly caste or class. The highest authority within a community usually sponsored its cults and sacrifices, officiated as its priest and promoted its assistants and acolytes. Specialists from the religious colleges and professionals such as haruspices and oracles were available for consultation. In household cult, the paterfamilias functioned as priest, and members of his familia as acolytes and assistants. Public cults required greater knowledge and expertise. The earliest public priesthoods were probably the flamines (the singular is flamen), attributed to king Numa: the major flamines, dedicated to Jupiter, Mars and Quirinus, were traditionally drawn from patrician families. Twelve lesser flamines were each dedicated to a single deity, whose archaic nature is indicated by the relative obscurity of some. Flamines were constrained by the requirements of ritual purity; Jupiter's flamen in particular had virtually no simultaneous capacity for a political or military career.[72]

In the Regal era, a rex sacrorum (king of the sacred rites) supervised regal and state rites in conjunction with the king (rex) or in his absence, and announced the public festivals. He had little or no civil authority. With the abolition of monarchy, the collegial power and influence of the Republican pontifices increased. By the late Republican era, the flamines were supervised by the pontifical collegia. The rex sacrorum had become a relatively obscure priesthood with an entirely symbolic title: his religious duties still included the daily, ritual announcement of festivals and priestly duties within two or three of the latter but his most important priestly role – the supervision of the Vestals and their rites – fell to the more politically powerful and influential pontifex maximus.[73]

Public priests were appointed by the collegia. Once elected, a priest held permanent religious authority from the eternal divine, which offered him lifetime influence, privilege and immunity. Therefore, civil and religious law limited the number and kind of religious offices allowed an individual and his family. Religious law was collegial and traditional; it informed political decisions, could overturn them, and was difficult to exploit for personal gain.[74]

Priesthood was a costly honour: in traditional Roman practice, a priest drew no stipend. Cult donations were the property of the deity, whose priest must provide cult regardless of shortfalls in public funding – this could mean subsidy of acolytes and all other cult maintenance from personal funds.[75] For those who had reached their goal in the Cursus honorum, permanent priesthood was best sought or granted after a lifetime's service in military or political life, or preferably both: it was a particularly honourable and active form of retirement which fulfilled an essential public duty. For a freedman or slave, promotion as one of the Compitalia seviri offered a high local profile, and opportunities in local politics; and therefore business.[76]

During the Imperial era, priesthood of the Imperial cult offered provincial elites full Roman citizenship and public prominence beyond their single year in religious office; in effect, it was the first step in a provincial cursus honorum. In Rome, the same Imperial cult role was performed by the Arval Brethren, once an obscure Republican priesthood dedicated to several deities, then co-opted by Augustus as part of his religious reforms. The Arvals offered prayer and sacrifice to Roman state gods at various temples for the continued welfare of the Imperial family on their birthdays, accession anniversaries and to mark extraordinary events such as the quashing of conspiracy or revolt. Every 3 January they consecrated the annual vows and rendered any sacrifice promised in the previous year, provided the gods had kept the Imperial family safe for the contracted time.[77]

A Roman sculpture depicting a Vestal

The Vestals were a public priesthood of six women devoted to the cultivation of Vesta, goddess of the hearth of the Roman state and its vital flame. A girl chosen to be a Vestal achieved unique religious distinction, public status and privileges, and could exercise considerable political influence. Upon entering her office, a Vestal was emancipated from her father's authority. In archaic Roman society, these priestesses were the only women not required to be under the legal guardianship of a man, instead answering directly to the Pontifex Maximus.[78]

A Vestal's dress represented her status outside the usual categories that defined Roman women, with elements of both virgin bride and daughter, and Roman matron and wife.[79] Unlike male priests, Vestals were freed of the traditional obligations of marrying and producing children, and were required to take a vow of chastity that was strictly enforced: a Vestal polluted by the loss of her chastity while in office was buried alive.[80] Thus the exceptional honor accorded a Vestal was religious rather than personal or social; her privileges required her to be fully devoted to the performance of her duties, which were considered essential to the security of Rome.[81]

The Vestals embody the profound connection between domestic cult and the religious life of the community.[82] Any householder could rekindle their own household fire from Vesta's flame. The Vestals cared for the Lares and Penates of the state that were the equivalent of those enshrined in each home. Besides their own festival of Vestalia, they participated directly in the rites of Parilia, Parentalia and Fordicidia. Indirectly, they played a role in every official sacrifice; among their duties was the preparation of the mola salsa, the salted flour that was sprinkled on every sacrificial victim as part of its immolation.[83]

One mythological tradition held that the mother of Romulus and Remus was a Vestal virgin of royal blood. A tale of miraculous birth also attended on Servius Tullius, sixth king of Rome, son of a virgin slave-girl impregnated by a disembodied phallus arising mysteriously on the royal hearth; the story was connected to the fascinus that was among the cult objects under the guardianship of the Vestals.

Augustus' religious reformations raised the funding and public profile of the Vestals. They were given high-status seating at games and theatres. The emperor Claudius appointed them as priestesses to the cult of the deified Livia, wife of Augustus.[84] They seem to have retained their religious and social distinctions well into the 4th century, after political power within the Empire had shifted to the Christians. When the Christian emperor Gratian refused the office of pontifex maximus, he took steps toward the dissolution of the order. His successor Theodosius I extinguished Vesta's sacred fire and vacated her temple.

Public religion took place within a sacred precinct that had been marked out ritually by an augur. The original meaning of the Latin word templum was this sacred space, and only later referred to a building.[45] Rome itself was an intrinsically sacred space; its ancient boundary (pomerium) had been marked by Romulus himself with oxen and plough; what lay within was the earthly home and protectorate of the gods of the state. In Rome, the central references for the establishment of an augural templum appear to have been the Via Sacra (Sacred Way) and the pomerium.[85] Magistrates sought divine opinion of proposed official acts through an augur, who read the divine will through observations made within the templum before, during and after an act of sacrifice.[86]

Divine disapproval could arise through unfit sacrifice, errant rites (vitia) or an unacceptable plan of action. If an unfavourable sign was given, the magistrate could repeat the sacrifice until favourable signs were seen, consult with his augural colleagues, or abandon the project. Magistrates could use their right of augury (ius augurum) to adjourn and overturn the process of law, but were obliged to base their decision on the augur's observations and advice. For Cicero, himself an augur, this made the augur the most powerful authority in the Late Republic.[87] By his time (mid 1st century BC) augury was supervised by the college of pontifices, whose powers were increasingly woven into the magistracies of the cursus honorum.[88]

The bronze Liver of Piacenza is an Etruscan artifact that probably served as an instructional model for the haruspex

Haruspicy was also used in public cult, under the supervision of the augur or presiding magistrate. The haruspices divined the will of the gods through examination of entrails after sacrifice, particularly the liver. They also interpreted omens, prodigies and portents, and formulated their expiation. Most Roman authors describe haruspicy as an ancient, ethnically Etruscan "outsider" religious profession, separate from Rome's internal and largely unpaid priestly hierarchy, essential but never quite respectable.[89] During the mid-to-late Republic, the reformist Gaius Gracchus, the populist politician-general Gaius Marius and his antagonist Sulla, and the "notorious Verres" justified their very different policies by the divinely inspired utterances of private diviners. The Senate and armies used the public haruspices: at some time during the late Republic, the Senate decreed that Roman boys of noble family be sent to Etruria for training in haruspicy and divination. Being of independent means, they would be better motivated to maintain a pure, religious practice for the public good.[90] The motives of private haruspices – especially females – and their clients were officially suspect: none of this seems to have troubled Marius, who employed a Syrian prophetess.[91]

Omens observed within or from a divine augural templum – especially the flight of birds – were sent by the gods in response to official queries. A magistrate with ius augurium (the right of augury) could declare the suspension of all official business for the day (obnuntiato) if he deemed the omens unfavourable.[92] Conversely, an apparently negative omen could be re-interpreted as positive, or deliberately blocked from sight.[93]

Prodigies were transgressions in the natural, predictable order of the cosmos – signs of divine anger that portended conflict and misfortune. The Senate decided whether a reported prodigy was false, or genuine and in the public interest, in which case it was referred to the public priests, augurs and haruspices for ritual expiation.[94] In 207 BC, during one of the Punic Wars' worst crises, the Senate dealt with an unprecedented number of confirmed prodigies whose expiation would have involved "at least twenty days" of dedicated rites.[95]

Livy presents these as signs of widespread failure in Roman religio. The major prodigies included the spontaneous combustion of weapons, the apparent shrinking of the sun's disc, two moons in a daylit sky, a cosmic battle between sun and moon, a rain of red-hot stones, a bloody sweat on statues, and blood in fountains and on ears of corn: all were expiated by sacrifice of "greater victims". The minor prodigies were less warlike but equally unnatural; sheep become goats, a hen become a cock (and vice versa) – these were expiated with "lesser victims". The discovery of an androgynous four-year-old child was expiated by its drowning[96] and the holy procession of 27 virgins to the temple of Juno Regina, singing a hymn to avert disaster: a lightning strike during the hymn rehearsals required further expiation.[97] Religious restitution is proved only by Rome's victory.[98][99]

In the wider context of Graeco-Roman religious culture, Rome's earliest reported portents and prodigies stand out as atypically dire. Whereas for Romans, a comet presaged misfortune, for Greeks it might equally signal a divine or exceptionally fortunate birth.[100] In the late Republic, a daytime comet at the murdered Julius Caesar's funeral games confirmed his deification; a discernible Greek influence on Roman interpretation.[101]

Dionysus (Bacchus) with long torch sitting on a throne, with Helios (Sol), Aphrodite (Venus) and other gods. Wall-painting from Pompeii, Italy

Rome's government, politics and religion were dominated by an educated, male, landowning military aristocracy. Approximately half of Rome's population were slave or free non-citizens. Most others were plebeians, the lowest class of Roman citizens. Less than a quarter of adult males had voting rights; far fewer could actually exercise them. Women had no vote.[142] However, all official business was conducted under the divine gaze and auspices, in the name of the Senate and people of Rome. "In a very real sense the senate was the caretaker of the Romans’ relationship with the divine, just as it was the caretaker of their relationship with other humans".[143]

The links between religious and political life were vital to Rome's internal governance, diplomacy and development from kingdom, to Republic and to Empire. Post-regal politics dispersed the civil and religious authority of the kings more or less equitably among the patrician elite: kingship was replaced by two annually elected consular offices. In the early Republic, as presumably in the regal era, plebeians were excluded from high religious and civil office, and could be punished for offenses against laws of which they had no knowledge.[144] They resorted to strikes and violence to break the oppressive patrician monopolies of high office, public priesthood, and knowledge of civil and religious law. The Senate appointed Camillus as dictator to handle the emergency; he negotiated a settlement, and sanctified it by the dedication of a temple to Concordia.[145] The religious calendars and laws were eventually made public. Plebeian tribunes were appointed, with sacrosanct status and the right of veto in legislative debate. In principle, the augural and pontifical colleges were now open to plebeians.[146] In reality, the patrician and to a lesser extent, plebeian nobility dominated religious and civil office throughout the Republican era and beyond.[147]

Temple of Bacchus ("Temple of the Sun"), c. 150 AD

While the new plebeian nobility made social, political and religious inroads on traditionally patrician preserves, their electorate maintained their distinctive political traditions and religious cults.[148] During the Punic crisis, popular cult to Dionysus emerged from southern Italy; Dionysus was equated with Father Liber, the inventor of plebeian augury and personification of plebeian freedoms, and with Roman Bacchus. Official consternation at these enthusiastic, unofficial Bacchanalia cults was expressed as moral outrage at their supposed subversion, and was followed by ferocious suppression. Much later, a statue of Marsyas, the silen of Dionysus flayed by Apollo, became a focus of brief symbolic resistance to Augustus' censorship. Augustus himself claimed the patronage of Venus and Apollo; but his settlement appealed to all classes. Where loyalty was implicit, no divine hierarchy need be politically enforced; Liber's festival continued.[149][150]

The Augustan settlement built upon a cultural shift in Roman society. In the middle Republican era, even Scipio's tentative hints that he might be Jupiter's special protege sat ill with his colleagues.[151] Politicians of the later Republic were less equivocal; both Sulla and Pompey claimed special relationships with Venus. Julius Caesar went further; he claimed her as his ancestress, and thus an intimate source of divine inspiration for his personal character and policies. In 63 BC, his appointment as pontifex maximus "signaled his emergence as a major player in Roman politics".[152] Likewise, political candidates could sponsor temples, priesthoods and the immensely popular, spectacular public ludi and munera whose provision became increasingly indispensable to the factional politics of the Late Republic.[153] Under the principate, such opportunities were limited by law; priestly and political power were consolidated in the person of the princeps ("first citizen").

Because of you we are living, because of you we can travel the seas, because of you we enjoy liberty and wealth. —A thanksgiving prayer offered in Naples' harbour to the princeps Augustus, on his return from Alexandria in 14 AD, shortly before his death.[154]

Wedding of Jupiter King of the Gods, and Juno, Queen of Heaven and goddess of marriage, and women. Fresco in Pompeii

By the end of the regal period Rome had developed into a city-state, with a large plebeian, artisan class excluded from the old patrician gentes and from the state priesthoods. The city had commercial and political treaties with its neighbours; according to tradition, Rome's Etruscan connections established a temple to Minerva on the predominantly plebeian Aventine; she became part of a new Capitoline triad of Jupiter, Juno and Minerva, installed in a Capitoline temple, built in an Etruscan style and dedicated in a new September festival, Epulum Jovis.[155] These are supposedly the first Roman deities whose images were adorned, as if noble guests, at their own inaugural banquet.

Rome's diplomatic agreement with its neighbours of Latium confirmed the Latin league and brought the cult of Diana from Aricia to the Aventine.[156] and established on the Aventine in the "commune Latinorum Dianae templum":[157] At about the same time, the temple of Jupiter Latiaris was built on the Alban mount, its stylistic resemblance to the new Capitoline temple pointing to Rome's inclusive hegemony. Rome's affinity to the Latins allowed two Latin cults within the pomoerium.[158] The cult to Hercules at the ara maxima in the Forum Boarium was established through commercial connections with Tibur.[159] The Tusculan cult of Castor as the patron of cavalry found a home close to the Forum Romanum:[160] Juno Sospita and Juno Regina were brought from Italy, and Fortuna Primigenia from Praeneste. In 217, the Venus of Eryx was brought from Sicily and installed in a temple on the Capitoline hill.[161]

A fresco from Pompeii depicting Hercules, Hyllus, Deianira, and the centaur Nessus from Greco-Roman mythology, 30–45 AD

The introduction of new or equivalent deities coincided with Rome's most significant aggressive and defensive military forays. Livy attributed the disasters of the early part of Rome's second Punic War to a growth of superstitious cults, errors in augury and the neglect of Rome's traditional gods, whose anger was expressed directly through Rome's defeat at Cannae (216 BC). The Sibylline books were consulted. They recommended a general vowing of the ver sacrum[162] and in the following year, the living burial of two Greeks and two Gauls; not the first nor the last sacrifice of its kind, according to Livy.

In 206 BC, during the Punic crisis, the Sibylline books recommended the introduction of a cult to the Magna Mater (Great Mother) from Pessinus, supposedly an ancestral goddess of Romans and Trojans. She was installed on the Palatine in 191 BC.

Deities with troublesome followers were taken over, not banned. An unofficial, popular mystery cult to Bacchus was officially taken over, restricted and supervised as potentially subversive in 186 BC.[163]

Mars caresses Venus enthroned. Wall-painting in Pompeii, c. 20 BC – 50s AD

The priesthoods of most Roman deities with clearly Greek origins used an invented version of Greek costume and ritual, which Romans called "Greek rites." The spread of Greek literature, mythology and philosophy offered Roman poets and antiquarians a model for the interpretation of Rome's festivals and rituals, and the embellishment of its mythology. Ennius translated the work of Graeco-Sicilian Euhemerus, who explained the genesis of the gods as deified mortals. In the last century of the Republic, Epicurean and particularly Stoic interpretations were a preoccupation of the literate elite, most of whom held – or had held – high office and traditional Roman priesthoods; notably, Scaevola and the polymath Varro. For Varro – well versed in Euhemerus' theory – popular religious observance was based on a necessary fiction; what the people believed was not itself the truth, but their observance led them to as much higher truth as their limited capacity could deal with. Whereas in popular belief deities held power over mortal lives, the skeptic might say that mortal devotion had made gods of mortals, and these same gods were only sustained by devotion and cult.

Just as Rome itself claimed the favour of the gods, so did some individual Romans. In the mid-to-late Republican era, and probably much earlier, many of Rome's leading clans acknowledged a divine or semi-divine ancestor and laid personal claim to their favour and cult, along with a share of their divinity. Most notably in the very late Republic, the Julii claimed Venus Genetrix as an ancestor; this would be one of many foundations for the Imperial cult. The claim was further elaborated and justified in Vergil's poetic, Imperial vision of the past.[8]

Fresco of Neptune and Salacia, Pompeii

In the late Republic, the so-called Marian reforms supposedly did the following: lowered an existing property bar on conscription, increased the efficiency of Rome's armies, and made them available as instruments of political ambition and factional conflict.[164] The consequent civil wars led to changes at every level of Roman society. Augustus' principate established peace and subtly transformed Rome's religious life – or, in the new ideology of Empire, restored it (see below).

Sissel Undheim has argued that, with their Religions of Rome volumes, Mary Beard, John North, and Simon Price dismantled the well-established narrative of the decline of religious in the late Republic, opening the way for more innovative and dynamic perspectives.[165] Towards the end of the Republic, religious and political offices became more closely intertwined; the office of pontifex maximus became a de facto consular prerogative.[88] Augustus was personally vested with an extraordinary breadth of political, military and priestly powers; at first temporarily, then for his lifetime. He acquired or was granted an unprecedented number of Rome's major priesthoods, including that of pontifex maximus; as he invented none, he could claim them as traditional honours. His reforms were represented as adaptive, restorative and regulatory, rather than innovative; most notably his elevation (and membership) of the ancient Arvales, his timely promotion of the plebeian Compitalia shortly before his election and his patronage of the Vestals as a visible restoration of Roman morality.[166] Augustus obtained the pax deorum, maintained it for the rest of his reign and adopted a successor to ensure its continuation. This remained a primary religious and social duty of emperors.

Bellerophon, Pegasus, and Athena (Minerva), fresco of the 3rd style from Pompeii, first half of the 1st century

Under the rule of Augustus, there existed a deliberate campaign to reinstate previously held belief systems amongst the Roman population. These once held ideals had been eroded and met with cynicism by this time.[167] The imperial order emphasized commemoration of great men and events which led to the concept and practice of divine kingship. Emperors postceding Augustus subsequently held the office of Chief Priest (pontifex maximus) combining both political and religious supremacy under one title.[104]

Mithras in a Roman wall painting

The Roman Empire expanded to include different peoples and cultures; in principle, Rome followed the same inclusionist policies that had recognised Latin, Etruscan and other Italian peoples, cults and deities as Roman. Those who acknowledged Rome's hegemony retained their own cult and religious calendars, independent of Roman religious law.[168] Newly municipal Sabratha built a Capitolium near its existing temple to Liber Pater and Serapis. Autonomy and concord were official policy, but new foundations by Roman citizens or their Romanised allies were likely to follow Roman cultic models.[169] Romanisation offered distinct political and practical advantages, especially to local elites. All the known effigies from the 2nd century AD forum at Cuicul are of emperors or Concordia. By the middle of the 1st century AD, Gaulish Vertault seems to have abandoned its native cultic sacrifice of horses and dogs in favour of a newly established, Romanised cult nearby: by the end of that century, Sabratha's so-called tophet was no longer in use.[170] Colonial and later Imperial provincial dedications to Rome's Capitoline Triad were a logical choice, not a centralised legal requirement.[171] Major cult centres to "non-Roman" deities continued to prosper: notable examples include the magnificent Alexandrian Serapium, the temple of Aesculapeus at Pergamum and Apollo's sacred wood at Antioch.[172]

The overall scarcity of evidence for smaller or local cults does not always imply their neglect; votive inscriptions are inconsistently scattered throughout Rome's geography and history. Inscribed dedications were an expensive public declaration, one to be expected within the Graeco-Roman cultural ambit but by no means universal. Innumerable smaller, personal or more secretive cults would have persisted and left no trace.[173]

Military settlement within the empire and at its borders broadened the context of Romanitas. Rome's citizen-soldiers set up altars to multiple deities, including their traditional gods, the Imperial genius and local deities – sometimes with the usefully open-ended dedication to the diis deabusque omnibus (all the gods and goddesses). They also brought Roman "domestic" deities and cult practices with them.[174] By the same token, the later granting of citizenship to provincials and their conscription into the legions brought their new cults into the Roman military.[175]

Traders, legions and other travellers brought home cults originating from Egypt, Greece, Iberia, India and Persia. The cults of Cybele, Isis, Mithras, and Sol Invictus were particularly important. Some of those were initiatory religions of intense personal significance, similar to Christianity in those respects.

The Maison Carrée in Nîmes, one of the best-preserved Roman temples. It is a mid-sized Augustan provincial temple of the Imperial cult.

In the early Imperial era, the princeps (lit. "first" or "foremost" among citizens) was offered genius-cult as the symbolic paterfamilias of Rome. His cult had further precedents: popular, unofficial cult offered to powerful benefactors in Rome: the kingly, god-like honours granted a Roman general on the day of his triumph; and in the divine honours paid to Roman magnates in the Greek East from at least 195 BC.[176][177]

The deification of deceased emperors had precedent in Roman domestic cult to the dii parentes (deified ancestors) and the mythic apotheosis of Rome's founders. A deceased emperor granted apotheosis by his successor and the Senate became an official State divus (divinity). Members of the Imperial family could be granted similar honours and cult; an Emperor's deceased wife, sister or daughter could be promoted to diva (female divinity).

The first and last Roman known as a living divus was Julius Caesar, who seems to have aspired to divine monarchy; he was murdered soon after. Greek allies had their own traditional cults to rulers as divine benefactors, and offered similar cult to Caesar's successor, Augustus, who accepted with the cautious proviso that expatriate Roman citizens refrain from such worship; it might prove fatal.[178] By the end of his reign, Augustus had appropriated Rome's political apparatus – and most of its religious cults – within his "reformed" and thoroughly integrated system of government. Towards the end of his life, he cautiously allowed cult to his numen. By then the Imperial cult apparatus was fully developed, first in the Eastern Provinces, then in the West.[179] Provincial Cult centres offered the amenities and opportunities of a major Roman town within a local context; bathhouses, shrines and temples to Roman and local deities, amphitheatres and festivals. In the early Imperial period, the promotion of local elites to Imperial priesthood gave them Roman citizenship.[180]

In an empire of great religious and cultural diversity, the Imperial cult offered a common Roman identity and dynastic stability. In Rome, the framework of government was recognisably Republican. In the Provinces, this would not have mattered; in Greece, the emperor was "not only endowed with special, super-human abilities, but... he was indeed a visible god" and the little Greek town of Akraiphia could offer official cult to "liberating Zeus Nero for all eternity".[181]

In Rome, state cult to a living emperor acknowledged his rule as divinely approved and constitutional. As princeps (first citizen) he must respect traditional Republican mores; given virtually monarchic powers, he must restrain them. He was not a living divus but father of his country (pater patriae), its pontifex maximus (greatest priest) and at least notionally, its leading Republican. When he died, his ascent to heaven, or his descent to join the dii manes was decided by a vote in the Senate. As a divus, he could receive much the same honours as any other state deity – libations of wine, garlands, incense, hymns and sacrificial oxen at games and festivals. What he did in return for these favours is unknown, but literary hints and the later adoption of divus as a title for Christian Saints suggest him as a heavenly intercessor.[182] In Rome, official cult to a living emperor was directed to his genius; a small number refused this honour and there is no evidence of any emperor receiving more than that. In the crises leading up to the Dominate, Imperial titles and honours multiplied, reaching a peak under Diocletian. Emperors before him had attempted to guarantee traditional cults as the core of Roman identity and well-being; refusal of cult undermined the state and was treasonous.[183]

Jewish ritual objects in 2nd-century gold glass from Rome

For at least a century before the establishment of the Augustan principate, Jews and Judaism were tolerated in Rome by diplomatic treaty with Judaea's Hellenised elite. Diaspora Jews had much in common with the overwhelmingly Hellenic or Hellenised communities that surrounded them. Early Italian synagogues have left few traces; but one was dedicated in Ostia around the mid-1st century BC and several more are attested during the Imperial period. Judaea's enrollment as a client kingdom in 63 BC increased the Jewish diaspora; in Rome, this led to closer official scrutiny of their religion. Their synagogues were recognised as legitimate collegia by Julius Caesar. By the Augustan era, the city of Rome was home to several thousand Jews.[184][185] In some periods under Roman rule, Jews were legally exempt from official sacrifice, under certain conditions. Judaism was a superstitio to Cicero, but the Church Father Tertullian described it as religio licita (an officially permitted religion) in contrast to Christianity.[186]

The Christian Martyrs' Last Prayer, by Jean-Léon Gérôme (1883)

Roman investigations into early Christianity found it an irreligious, novel, disobedient, even atheistic sub-sect of Judaism: it appeared to deny all forms of religion and was therefore superstitio. By the end of the Imperial era, Nicene Christianity was the one permitted Roman religio; all other cults were heretical or pagan superstitiones.[187]

After the Great Fire of Rome in 64 AD, Emperor Nero accused the Christians as convenient scapegoats, who were later persecuted and killed. From that point on, Roman official policy towards Christianity tended towards persecution. During the various Imperial crises of the 3rd century, "contemporaries were predisposed to decode any crisis in religious terms", regardless of their allegiance to particular practices or belief systems. Christianity drew its traditional base of support from the powerless, who seemed to have no religious stake in the well-being of the Roman State, and therefore threatened its existence.[188] The majority of Rome's elite continued to observe various forms of inclusive Hellenistic monism; Neoplatonism in particular accommodated the miraculous and the ascetic within a traditional Graeco-Roman cultic framework. Christians saw these practices as ungodly, and a primary cause of economic and political crisis.

In the wake of religious riots in Egypt, the emperor Decius decreed that all subjects of the Empire must actively seek to benefit the state through witnessed and certified sacrifice to "ancestral gods" or suffer a penalty: only Jews were exempt.[189] Decius' edict appealed to whatever common mos maiores (ancestors' customs) might reunite a politically and socially fractured Empire and its multitude of cults; no ancestral gods were specified by name. The fulfillment of sacrificial obligation by loyal subjects would define them and their gods as Roman.[190][191] Apostasy was sought, rather than capital punishment.[192] A year after its due deadline, the edict expired.[193]

Nero's Torches, by Henryk Siemiradzki (1876). According to Tacitus, Nero used Christians as human torches

Valerian singled out Christianity as a particularly self-interested and subversive foreign cult, outlawed its assemblies and urged Christians to sacrifice to Rome's traditional gods.[194][195] In another edict, he described Christianity as a threat to Empire – not yet at its heart but close to it, among Rome's equites and Senators. Christian apologists interpreted his eventual fate – a disgraceful capture and death – as divine judgement. The next forty years were peaceful; the Christian church grew stronger and its literature and theology gained a higher social and intellectual profile, due in part to its own search for political toleration and theological coherence. Origen discussed theological issues with traditionalist elites in a common Neoplatonist frame of reference – he had written to Decius' predecessor Philip the Arab in similar vein – and Hippolytus recognised a "pagan" basis in Christian heresies.[196] The Christian churches were disunited; Paul of Samosata, Bishop of Antioch was deposed by a synod of 268 both for his doctrines, and for his unworthy, indulgent, elite lifestyle.[197] Meanwhile, Aurelian (270-75) appealed for harmony among his soldiers (concordia militum), stabilised the Empire and its borders and successfully established an official, Hellenic form of unitary cult to the Palmyrene Sol Invictus in Rome's Campus Martius.[198]

The Victory of Faith, by Saint George Hare, depicts two Christians in the eve of their damnatio ad bestias

In 295, Maximilian of Tebessa refused military service; in 298 Marcellus renounced his military oath. Both were executed for treason; both were Christians.[194] At some time around 302, a report of ominous haruspicy in Diocletian's domus and a subsequent (but undated) dictat of placatory sacrifice by the entire military triggered a series of edicts against Christianity.[199] The first (303 AD) "ordered the destruction of church buildings and Christian texts, forbade services to be held, degraded officials who were Christians, re-enslaved imperial freedmen who were Christians, and reduced the legal rights of all Christians... [Physical] or capital punishments were not imposed on them" but soon after, several Christians suspected of attempted arson in the palace were executed.[200] The second edict threatened Christian priests with imprisonment and the third offered them freedom if they performed sacrifice.[201] An edict of 304 enjoined universal sacrifice to traditional gods, in terms that recall the Decian edict.

In some cases and in some places the edicts were strictly enforced: some Christians resisted and were imprisoned or martyred. Others complied. Some local communities were not only pre-dominantly Christian, but powerful and influential; and some provincial authorities were lenient, notably the Caesar in Gaul, Constantius Chlorus, the father of Constantine I. Diocletian's successor Galerius maintained anti-Christian policy until his deathbed revocation in 311, when he asked Christians to pray for him. "This meant an official recognition of their importance in the religious world of the Roman empire, although one of the tetrarchs, Maximinus Daia, still oppressed Christians in his part of the empire up to 313."[202]

The Aula Palatina of Trier, Germany (then part of the Roman province of Gallia Belgica), built during the reign of Constantine I (r. 306-337 AD)

The conversion of Constantine I ended the Christian persecutions. Constantine successfully balanced his own role as an instrument of the pax deorum with the power of the Christian priesthoods in determining what was (in traditional Roman terms) auspicious – or in Christian terms, what was orthodox. The edict of Milan (313) redefined Imperial ideology as one of mutual toleration. Constantine had triumphed under the signum (sign) of the Christ: Christianity was therefore officially embraced along with traditional religions and from his new Eastern capital, Constantine could be seen to embody both Christian and Hellenic religious interests. He passed laws to protect Christians from persecution;[203] he also funded the building of churches, including Saint Peter's basilica. He may have officially ended – or attempted to end – blood sacrifices to the genius of living emperors, though his Imperial iconography and court ceremonial outstripped Diocletian's in their elevation of the emperor as somehow more than human.[204]

Constantine promoted orthodoxy in Christian doctrine, so that Christianity might become a unitary force, rather than divisive. He summoned Christian bishops to a meeting, later known as the First Council of Nicaea, at which some 318 bishops (mostly easterners) debated and decided what was orthodox, and what was heresy. The meeting reached consensus on the Nicene Creed.[205][206] At Constantine's death, he was honored as a Christian and as an Imperial "divus".[207] Later, Philostorgius would criticize those Christians who offered sacrifice at statues of the divus Constantine.[208]

Monogramme of Christ (the Chi Rho) on a plaque of a marble sarcophagus, 4th century CE (Musei Vaticani, here in a temporary exhibition at the Colosseum in Rome, Italy)

Christianity and traditional Roman religion proved incompatible. From the 2nd century onward, the Church Fathers had condemned the diverse non-Christian religions practiced throughout the Empire as "pagan".[209] Constantine's actions have been regarded by some scholars as causing the rapid growth of Christianity,[210] though many modern scholars disagree.[211][212] Constantine's unique form of Imperial orthodoxy did not outlast him. After his death in 337, two of his sons, Constantius II and Constans, took over the leadership of the empire and re-divided their Imperial inheritance. Constantius was an Arian and his brothers were Nicene Christians.

Constantine's nephew Julian rejected the "Galilean madness" of his upbringing for an idiosyncratic synthesis of neo-Platonism, Stoic asceticism and universal solar cult. Julian became Augustus in 361 and actively fostered a religious and cultural pluralism, attempting a restitution of non-Christian practices and rights.[213] He proposed the rebuilding of Jerusalem's temple as an Imperial project and argued against the "irrational impieties" of Christian doctrine.[214] His attempt to restore an Augustan form of principate, with himself as primus inter pares ended with his death in 363 in Persia, after which his reforms were reversed or abandoned. The empire once again fell under Christian control, this time permanently.

In 380, under Theodosius I, Nicene Christianity became the official state religion of the Roman Empire. Christian heretics as well as non-Christians were subject to exclusion from public life or persecution, though Rome's original religious hierarchy and many aspects of its ritual influenced Christian forms,[215] and many pre-Christian beliefs and practices survived in Christian festivals and local traditions.

The Western emperor Gratian refused the office of pontifex maximus, and against the protests of the Senate, removed the altar of Victory from the Senate house and began the disestablishment of the Vestals. Theodosius I briefly re-united the Empire: in 391 he officially adopted Nicene Christianity as the Imperial religion and ended official support for all other creeds and cults. He not only refused to restore Victory to the senate-house, but extinguished the Sacred fire of the Vestals and vacated their temple: the senatorial protest was expressed in a letter by Quintus Aurelius Symmachus to the Western and Eastern emperors. Ambrose, the influential Bishop of Milan and future saint, wrote urging the rejection of Symmachus's request for tolerance.[216] Yet Theodosius accepted comparison with Hercules and Jupiter as a living divinity in the panegyric of Pacatus, and despite his active dismantling of Rome's traditional cults and priesthoods could commend his heirs to its overwhelmingly Hellenic Senate in traditional Hellenic terms. He was the last emperor of both East and West.[217][218]