The supreme deity of the Roman pantheon, mighty Jupiter was a god of sky and thunder whose symbols were the oak tree and eagle. He ruled as the dominant member of a triumvirate called the Capitoline Triad, which included his consort Juno and daughter Minerva. Jupiter bore many similarities to Zeus, the king of the Greek deities from whom he was adapted.
Unlike Zeus, however, Jupiter was explicitly linked to a specific political entity—Rome. From the great temple erected in his honor on the Capitoline Hill in Rome, Jupiter presided over the state and its ever-expanding empire. As a result, the Romans emphasized the worship of Jupiter above all other gods. Jupiter’s blessings were thought to secure their victories and maintain hegemony over their rivals. Worship of Jupiter was formalized by the Roman state over the course of its existence.
What is known of Jupiter’s mythos came not through the narratives in which he plays a role, but from the ways in which his worship was observed by the Romans. Like other figures in Roman mythology, Jupiter was believed to be a critical actor in Roman history. Accordingly, his nature and attributes transformed in order to keep up with broader historical changes in the Roman state. By the end of the first century BCE, Jupiter’s centrality to the state was eclipsed by cults devoted to the worship of deified emperors.
In Latin, the name “Jupiter” was usually rendered as Iūpiter or Iuppiter (the character “j” was not a part of ancient Latin alphabet, and was added in the Middle Ages). The name stemmed from two roots. One was the Proto Indo-European word dyeu- (the same root for the name “Zeus”!), meaning “shining thing,” “sky,” or “day” (as in the Latin for day dies); the other was pater, a word shared by Greek and Latin that means “father.” In keeping with these naming conventions, Jupiter was sometimes called Diespiter or Dispiter. Additionally, Zeus was called Zeu Pater in Greek, and Sanskrit speakers used the term Dyaus pitar (father of heavens) to refer to the sky god. This all points an archetypal “sky father” deep in the history of Indo-European-speaking people, whose identity was localized by the cultures that splintered off over time.
Jupiter was known by a number of epithets. For bringing victory, he was Iuppiter Elicius, or “Jupiter who brings forth,” and for summoning lightning, he was Iuppiter Fulgur, or “lightning Jupiter.” For bringing light and enlightenment to all things, he was Iuppiter Lucetius, or “Jupiter of the light,” as well as Iuppiter Caelestis, or “Jupiter of the heavens.” Above all, he was Iuppiter Optimus Maximus: “Jupiter, the best and greatest.”
As the god of the sky, Jupiter commanded lightning, thunder, and storms. Like Zeus, he wielded lightning bolts as weapons. Befitting his role as king of the gods, Jupiter was commonly depicted sitting on a throne and holding a royal scepter and staff.
Rather than taking an active part in battles, however, Jupiter was imagined to oversee and control them. More than any other deity, Jupiter held the fate of the Roman state in the balance. To appease him, Romans offered sacrifice and took sacred oaths in his honor. The faithfulness with which they made sacrificial offerings and kept their oaths informed Jupiter’s bearing. The Romans came to believe that the success of their Mediterranean empire could be attributed to their unique devotion to Jupiter.
By way of the eagle, Jupiter also guided the taking of the auspices, the practice of divination whereby augurs tried to decipher omens and predict the future by observing the flight of birds (words such as “auspicious” and “inauspicious” come from this practice). Because the eagle was Jupiter’s sacred animal, the Romans believed that the bird’s behavior communicated his will. Omens divined through the behavior of eagles were considered to be the most revealing.
Jupiter was the son of Saturn—the god of the sky who preceded Jupiter—and Ops (or Opis), goddess of the earth and growth. His brothers were Neptune, god of the sea, and Pluto, god of the underworld and wealth (metals, the basis of Roman coinage and wealth, were found underground). His sisters included Ceres, a fertility goddess who controlled the growth of grains, Vesta, goddess of hearth and home, and Juno, a maternal goddess associated with marriage, family, domestic tranquility, and the moon.
Jupiter was married to his sister Juno, who served as the Roman counterpart to Hera. Among their children were Mars, the god of war that played a substantial role in the founding of Rome, and Bellona, a goddess of war. Additional children included Vulcan, the god of fire, metalworking, and the forge, and Juventus, a youthful goddess who oversaw the transition from childhood to adulthood and was associated with invigoration and rejuvenation.
Though the Roman mythic corpus lacked the stories of marital strife that so often defined Zeus and Hera’s relationship, it was clear that Jupiter was unfaithful to Juno. Anecdotal tales told of Jupiter’s many infidelities and the children that resulted from them. With Maia, the goddess of earth and fertility (who may have lent her name to the Roman month Maius, or May), Jupiter had Mercury, the messenger god of commerce, merchants, sailing, and travel. With Dione, he sired Venus, goddess of love and sexual desire (although other stories had her emerging from sea foam, like the Greek Aphrodite). With his sister Ceres, Jupiter had Proserpine, an important cultic figure associated with cycles of decay and rebirth, just as Persephone was for the Greeks. Finally, with Metis, whom he raped, Jupiter had Minerva.
By and large, Roman mythology lacked a rich narrative tradition. As such, little exists in the way of epic stories explaining the order of the universe and the origins of humankind. This is also true of Jupiter, whose mythos was built not around stories that featured him as a main character, but around the ways that Romans observed their chief deity and explained his place in their storied history.
Jupiter’s origins were largely identical to the tales of Zeus’ creation. Before Jupiter, Saturn reigned supreme as the god of the sky and the universe. Of course, it had not always been that way. Before Saturn, his father Caelus (meaning “heavens”) ruled, but Saturn overthrew his father and took control of the heavens for himself. After Saturn married Ops and impregnated her, he learned of a prophecy foretelling his downfall at the hands of one of his children. To prevent the usurper from seeing life, he swallowed the first five children that sprang from Ops’ womb. When the last child finally emerged, Ops hid him away and gave Saturn a rock dressed in swaddling instead. An unsuspecting Saturn devoured the rock whole.
What followed was the worst case of indigestion in the history of mythology. Unable to digest the rock, Saturn regurgitated it, along with the five children he had swallowed—Ceres, Juno, Neptune, Pluto, and Vesta. Jupiter, meanwhile, had been plotting his father’s imminent demise. With the help of his brothers and sisters, he defeated Saturn and took control of the cosmos.
Jupiter would later find himself in the same position as his father, Saturn. After raping and impregnating Metis, Jupiter was seized with the fear that his own unborn son might overthrow him. To avoid such a fate, Jupiter swallowed Metis along with her unborn child. Much to Jupiter’s surprise, the child did not die, but continued to grow until it burst from his forehead and into the world. That child was Minerva, the goddess of wisdom, forethought, and strategic warfare; she eventually became a part of the ruling Capitoline Triad.
Jupiter, Numa, and the Founding of Rome
According to the mythologized history of the founding of Rome, Numa Pompilius, the second king of Rome, introduced Jupiter to the Romans and established the parameters of his worship. In the early days of Rome, Jupiter ruled as part of the Archaic Triad, which also included Mars and Quirinus, a deified version of the city’s founder: Romulus.
As the histories of Livy and Plutarch had it, Numa was facing hardship and coerced two minor deities, Picus and Faunas, into summoning Jupiter to the Aventine Hill. There, Numa consulted with the mighty god, who issued his demands regarding the offering of sacrifices, known as hostiae.
In exchange for securing the worship of the Roman people, Jupiter taught Numa how to avoid lightning bolts, as per Numa’s demands. Jupiter’s lightning lesson likely served as a metaphor symbolizing his broader offer of protection and support for the Roman people. Jupiter, in fact, sealed the pact with Numa and the Romans by sending down from the heavens a perfectly round shield, called the ancile, a symbol of protection if ever there were one. In turn, Numa had eleven nearly identical copies of the ancile made. These twelve shields—known collectively as the ancilia—became a sacred symbol of the city and an enduring reminder of the compact between Jupiter and Rome.
Jupiter and the Roman State Religion
In time, Jupiter worship became a part of the well-established rituals organized and overseen by the state. The Romans built a grand temple to Jupiter Optimus Maximus n the Capitoline Hill; once complete, it was the greatest of all Roman temples. According to Roman mythology, it was the legendary fifth king of Rome, Tarquinius Priscus, who began construction of the temple, and the last Roman king, Tarquinius Superbus, who finished it in 509 BC. While the temple was destroyed well before the modern era, in its time the temple towered over the Capitoline. A statue of Jupiter driving a four-horse chariot could be found at the apex of the temple. A statue of Jupiter, painted red during celebrations, and a stone altar called Iuppiter Lapis (“the Jupiter Stone”), where oath-takers took their sacred vows, both lay inside the temple.
The temple of Jupiter Optimus Maximus served as a sacrificial site where Romans would offer slaughtered animals (known as hostiae) to the mighty god. The hostiae for Jupiter were the ox, the lamb (offered annually on the Ides of March), and the wether or castrated goat, which was offered on the Ides of January. To oversee these offerings, the Romans created the ecclesiastical position Flamen Dialis, the high priest of Jupiter. The Flamen Dialis also served as a ranking member of the college of Flamines, a body of fifteen priests who presided over the affairs of the state religion. So reverent was the office of Flamen Dialis that only those of aristocratic birth, the patricians, could occupy it (plebeians, or those of low birth, were forbidden).
The Temple of Jupiter Optimus Maximus was also the final destination of the celebratory military processions known as triumphs. Leading such processions was a triumphator, or victorious general. The procession itself would consist of the triumphator’s army, prisoners, and spoils, which would wind through the streets of Rome before ending up at the great temple. There, the procession offered sacrifices and left a portion of their spoils for Jupiter.
Throughout these festivities, the triumphator would bear the trappings of Jupiter himself. He would ride in a four-horse chariot, wear a purple toga, paint his face red, and even carry the scepter of Jupiter. As Maurus Servius Honoratus wrote in his Commentary on the Eclogues of Virgil, “The triumphing generals wear the insignia of Jupiter, the sceptre and toga ‘palmata,’ also known as being “in the coat of Jupiter,” while gazing with the red color of earth smeared on his face.” The triumphator was thought to literally embody the god as he rode toward Jupiter’s temple.
The Cult of Jupiter thrived in Rome from its founding, popularly dated to the eighth century BC, to at least the first century BC. The cult waned with the fall of the Republic and the rise of the Empire. During this time, the state redirected popular religious enthusiasm from the old gods to the deified Roman emperors. By the time the first emperors embraced Christianity in the fourth century CE, the mythology of Jupiter and the Roman pantheon had totally fallen out of favor.
In modern times, Jupiter was best known for lending his name to the fifth planet from the sun, the largest in our solar system. Readers may have also unwittingly channeled Jupiter by uttering the folksy exclamation “By Jove!” Another version of Jupiter’s name, Jove was seen as a more acceptable exclamation for pious Christians, who feared using the name of their own god in vain.
In most pop culture outlets, however, Zeus has been preferred to Jupiter, in keeping with the broader cultural preference for Greek deities over Roman ones.