Astrology and imperial legitimacy in ancient Rome

In the Roman Republic and Empire, political legitimacy was frequently bolstered by claims of divine favor. Roman emperors projected power through propaganda that drew inspiration from mythology, omens and religious symbolism.

Arienne King

In recent years, astrological apps and websites have skyrocketed in popularity as people coped with political unrest, climate change, and pandemics. A similar phenomenon occurred in the Late Roman Republic when the spectre of civil war and economic instability haunted society. In this environment of uncertainty, many Romans turned to various forms of divination in an attempt to know what dangers the future held in store.

The spread of astrology, a form of divination based on the movement of the stars, to Roman Italy added to the ideological arsenal of political propagandists. This proved to be a double-edged sword, as astrological predictions could also be used to erode confidence in the political establishment. Like other forms of divination, the Roman state sought to exploit the ideological value of these astrological predictions while preventing them from being co-opted by dissidents.

The arrival of astrology

The earliest references to astrology in Roman literature date to the third century BCE, when interest in Greek philosophy began to take root in Roman Italy. Hellenistic astrology became a topic of considerable interest to Stoic philosophers, but was also strongly associated with immigrants and slaves from Greece and the Near East. Because of its foreign associations, astrology was at first viewed with skepticism.

By the first century BCE, it had become popular among Rome’s educated aristocracy. Contemporary Roman authors often associate astrology with the lower classes, although it is known that many educated Romans from the aristocracy also took an interest in the practice. The only surviving Roman astrological texts were produced by educated elites, who discussed it through the framework of astronomy and natural philosophy.

Even in antiquity, skeptics noted astrology’s inconsistencies and overreliance on coincidence. The orator Cicero dismissed astrologers as “liars and people who had no fear of what the judgement of future centuries on them would be” (De Divinatione 1.19; transl. Wardle, pp. 57-58). It was also understood that many seers, including astrologers, preyed on their clients’ superstitions for financial gain. Concerns about the prevalence of spiritual fraud were the stated motivation behind the expulsion of astrologers and other magicians from Rome in 139 BCE.

However, it would be a mistake to assume that these skeptics represented the majority opinion in ancient Rome. Most Romans believed that the gods could make their will known through signs and omens, astrology being one of many popular forms of divination. The Roman state itself supported institutions of diviners like augurs (who looked for omens in the flight paths of birds) and haruspices (who read animal entrails for omens)who relayed and interpreted messages from the gods.

On Earth, as it is in Heaven

Events that threatened social stability, such as conflict or bad harvests, were especially common topics for astrological inquiry in the ancient world. When the world became unpredictable, people sought to make sense of its erratic turns and regain some control over their future.

In the earliest major surviving treatise on Roman astrology, the astrologer and poet Manilius describes the impact that the stars were believed to hold over human affairs in his Astronomica, written in ca. 14 CE (2.603-7; transl. Goold, p. 131):

Truly, since many are the signs in which men are born for discord, peace is banished throughout the world, and the bond of loyalty is rare and granted to few; and just as in heaven, so too is earth at war with itself, and the nations of mankind are subject to a destiny of strife.

In Greek and Roman astrology, the movement and opposition of the stars and planets were described as parallels to earthly wars and political rivalry. These celestial influences also extended to the fortunes of a city or state. Thus, some astrologers attempted to cast horoscopes for cities by reading the position of the planets at the time of their establishment. The scholar Varro, who lived in the first century BCE, commissioned a horoscope for both Rome and its mythic founder Romulus from Tarutius of Firmum.

Power & propaganda

Predictions about war or the fate of Rome had the potential to send shockwaves through the Republic, and prophecy was often leveraged as a tool for ancient political propaganda. The Roman state itself supported institutions of diviners like augurs and haruspices.

Astrological predictions and symbolism became a noticeable aspect of political propaganda during the first century BCE as the Roman Republic transitioned to an Empire. For example, the sea-goat symbolizing the star sign Capricorn, which was believed to bring good fortune, began to appear on Roman coins in the early first century BCE.

The increasing legitimacy of astrology as a political tool during the final days of the Roman Republic reflected the accumulation of power by strong individuals. In contrast to the more public forms of divination traditionally cited in Roman politics, astrology focused on the destiny of individuals and was carried out as a private enterprise (Barton 1994, p. 40). Astrological predictions about the leading men in Rome became popular as they vied for power. In some cases, these men patronized personal seers as advisors, while in other instances purported prophecies were attached to them posthumously.

Later authors claimed that astrologers made glowing – and dramatically false – predictions about the longevity of figures like Gnaeus Octavius, Crassus, Pompey, and Julius Caesar. By contrast, the dictator Sulla reportedly received an accurate prediction of his own natural death after consulting astrologers (Plutarch 37.1).

Destiny & Empire

Augustus used astrological propaganda more heavily than previous Roman statesmen. He used the appearance of Sidus Iulium (or Julian Star), a comet which appeared in July 44 BCE, to promote the idea that his adoptive father Julius Caesar had been deified upon his death. This gave way to more unorthodox attempts to link himself to divinity, many of which involved astrology.

Augustus even published a horoscope that foretold his meteoric rise to master of the Mediterranean. Numerous stories about his horoscope circulated in Rome during and after his lifetime, typically claiming that various astrologers had foreseen his success. Suetonius claims that a Greek astrologer named Theogenes predicted that Augustus would rise to great heights as did the senator and astrologer Nigidius Figulus.

Though it was not his birth sign, he was most strongly associated with Capricorn. This may have been because it was associated with the time of his conception rather than birth or because of its symbolic value. Capricorn was supposed to represent the spring of a new political era, as the sun enters the tropic of Capricorn on the eve of the winter solstice, when the days begin to lengthen (Barton 1990, p. 41).

During the Augustan period, astrological imagery became prominent in art and the first Latin astrological texts were produced. The precedent set by Augustus meant that astrology became intertwined with the performance of imperial power and legitimacy in the first century CE. The claim that the emperor’s reign was preordained became a standard component of imperial propaganda in subsequent generations. These stories of prophecies and omens fed into the perception that the Emperor’s reign was a function of destiny.

The relationship between emperors and astrology became a running theme in Roman literature. Retroactive predictions of greatness or betrayals are a staple of such narratives, as are anecdotes in which a coronation is carefully timed around the ideal astrological conditions. Some emperors, such as Hadrian and Septimius Severus, were even said to have had an aptitude for astrology themselves.

Many episodes involving interactions between emperors and astrologers in Roman literature focus on their perceived tyranny. Augustus’ unpopular successor Tiberius was reported to have surrounded himself with astrologers and to have killed ones who failed to impress him with their predictions. Roman authors repeated the trope of an emperor asking astrologers to identify potential threats to their reigns and executing influential men based on these predictions, applying it to rulers like Domitian (Cassius Dio 67.15.6) and Caracalla (Herodianus 3.12.1).

Astrologers and political dissent

Astrology was a double-edged sword, as those in power realized. Just as horoscopes and prophecies could be used to support the establishment, they could also be leveraged against it. The mere ability to plausibly suggest conflict or upheaval could be enough to influence political outcomes. An ambitious politician might seek to publish a prediction foretelling the downfall of a rival, which could be supplied by any astrologer who wanted to attach themselves to a rising star.

Several astrologers acted as supporters or advisors to rebels and political mavericks in the Roman Republic. Most notably, an astrologer named Athenio organized a slave revolt in Sicily around the prediction that he would become a king, which his initial successes must have made seem likely before he was killed in 100 BC (Diodorus Siculus 36.5-10). Astrologers are also implicated in inciting rebellion during the tumultuous Year of the Four Emperors, an indication of the uncertainty and opportunity that emerged in the wake of Nero’s death.

Throughout the Imperial period, astrologers were implicated in numerous conspiracies against the emperor. The first of these alleged conspiracies occurred during the reign of Tiberius, which saw the trial of Marcus Scribonius Libo Drusus, who was accused of using magic against the imperial family and visiting astrologers for treasonous purposes. Similar charges were leveled against others close to the imperial family in the first and second centuries CE.

Regulating astrology

Clearly, the business of prophecy was too dangerous to allow it to go unregulated. If astrology was to become a symbol of political legitimacy, then the emperor must have a monopoly on it. Under Roman law, astrologers were not permitted to make predictions about politics or the fate of the Roman Republic.

Augustus attempted to further restrict the actions of astrologers in 11 CE, making it illegal to consult them in private or ask questions about the timing of a person’s death (Volk 2009, p. 136). His advanced age likely motivated him to curb speculation about his health and longevity.

Astrologers took many steps to safeguard themselves from any accusation of treason, such as by making their responses to inquiries loudly and publicly, to prevent clients from asking illicit questions about the wellbeing of the imperial family or the state.

Despite attempts to limit the appropriate topics of astrological inquiry, seditious astrological predictions continued to be published anonymously and private inquiries often turned to treasonous subjects. Astrologers were banned from the city of Rome by senatorial decree numerous times during the imperial period, typically during times of social unrest when potential sources of sedition could not be tolerated.

After coming to power in Year of the Four Emperors, Vitellius issued an imperial edict outlawing astrology. Vitellius’ decision angered many astrologers, who published anonymous predictions about Vitellius’ downfall. In turn, he began executing practitioners of astrology.

After his defeat by Vespasian, astrologers evidently returned In later generations, other emperors would also expel astrologers during times of crises, with little success. The uneasy relationship between the emperor and astrology would continue through to late antiquity. Julius Firmicus Maternus, writing in the fourth century CE, advises astrologers to avoid questions about politics at all costs (Mathesis 2.30.4; transl. Barton, p 2):

Beware of replying to anyone about the condition of the State or the life of the Roman emperor. For it is not right, nor is it permitted, that from wicked curiosity we learn anything about the condition of the State…

By the fifth century, Christian opposition towards divination and increasing skepticism regarding astrology had eroded its popularity, and it did not experience a resurgence until the Late Middle Ages.