The Cult of Mithras: A Look at Ancient Rome’s Mystery Messiah

View of the Roman Forum at dawn from the Capitoline Hill.
© scaliger/

Mithras stands over the bull, his knife planted firmly into its heart.  He glares over his shoulder at the watching sun god, a look of defiance on his face.  A dog and snake reach toward the blood seeping from the dying bull’s wound while a scorpion attacks its genitals.  This is the scene carved into an altar to the Persian god Mithras beneath the Basilica di San Clemente, a 12th century Catholic Church in the heart of Rome.  Though a Christian church today, two millennia ago members of a very different religion worshiped at this site.  They were followers of the Cult of Mithras, a shadowy organization of which little is known.  Who were they and what did this mysterious bull slaying scene mean to them?  After centuries of study, we may at last be approaching an answer. 

Relics of Ancient Rome

I first visited the Basilica di San Clemente in 2019.  The Basilica is what Italians call a “lasagna” building.  That is, a building which sits on top of an older building which sits on top of another, still older structure.  These “lasagna” buildings vividly illustrate the degree to which Rome today was literally built on the foundations of the past. In the case of San Clemente, the existing structure (built in 1108 AD) lies above an older church, this one dating back to the fourth century.  This fourth century basilica was itself built upon older Roman buildings, including a mint and the house of a nobleman.  Each successive structure incorporated the previous buildings into its foundations.  If you visit San Clemente today, you can visit all three of these levels (the new church, the old, and the Roman buildings), which have been painstakingly excavated over the last hundred years. 

What really interested me, though, was what lie below the fourth century church in the old Roman buildings.  Here, a nobleman had converted a room of his house into a temple to Mithras.  The room follows the traditional layout for Mithraic temples – a long hall with a row of stone benches running down either side.  In the middle is an altar depicting the scene described above, Mithras slaying the bull.  Here, as in so many other Mithraic temples uncovered throughout the Roman Empire, a small group of 30 to 40 men would have feasted and conducted secret ceremonies in honor of their god, Mithras.

A Mithraic Temple discovered at Ostia Antica near Rome.  A large statue of Mithras slaying the bull stands at the center of the temple.  Rows of stone benches run parallel down the sides of the temple.
A Mithraic Temple at Ostia Antica, just outside Rome. (Michelle Touton – Wikicommons)

Mithras and Rome

The Roman Cult of Mithras began in the first century CE, reaching its height in the third century.  It was most popular among freed slaves, minor bureaucrats, and soldiers.  While centered in Rome, Mithraic temples have been found across the empire, including in Britain, North Africa, and Palestine. 

Scholars attribute the broad geographic distribution of Mithraic temples to the Cult’s popularity within the Roman military.  Soldiers took their beliefs to the far corners of the empire, constructing temples throughout the frontier.  At its height, the Cult of Mithras rivalled early Christianity as the dominant religion of Rome. 

Despite its broad following, little is known about the Cult of Mithras.  This is because the Cult of Mithras was a “mystery religion.”  In these religions, core teachings were shrouded in secrecy and revealed only to initiates.  As a result, there are no surviving accounts that fully explain the Cult’s primary tenants, rituals, or moral code.  This has left big gaps in our understanding of Mithraic beliefs, leaving intact much of its mystery. 

Chief among these mysteries is the meaning of the bull-slaying scene, known as the Tauroctony.  Found at the center of every Mithraic temple, the Tauroctony is always the same – Mithras, in a cave, slaying the bull.  A dog, a serpent, and a scorpion beneath.  The sun and moon gods, and occasionally the zodiac, are depicted overhead.  Rich in symbolism, it is the most important image in all of Roman Mithraism.  And despite over a century of studying it, scholars still do not agree on its meaning.

Marble relief carving of the Tauroctany at ROM Toronto.  The carving depicts Mithras looking out at the viewer as he slays the bull.
Marble relief carving of the Tauroctony (aka the bull-slaying scene) at ROM Toronto. © Reimar/

The Mystery of the Tauroctony

One of the first modern attempts to understand the Tauroctony was made by Franz-Valéry-Marie Cumont, who looked to Mithras’s Persian origins for an explanation.  Writing in 1896, he theorized that the image depicts a famous scene from Persia’s Zoroastrian religion, in which a “primordial bovine” is slain.  The death of the god-like bovine brings about new species of grain and populates the earth with new animal life.  In some Mithraic temples, the bull’s tail does appear to be turning into wheat, lending some support for this explanation.    

The only problem is that in the traditional Zoroastrian version of this story, it isn’t Mithras who slays the bovine but rather an evil spirit named Ahriman.  Cumont theorized that at some point, Mithras must have become a stand in for Ahriman.  Though speculative, Cumont’s theory went unquestioned for decades and became the most broadly accepted explanation of the meaning of the bull-slaying scene.  However, as the years went by and no further evidence connecting Mithras to the slaying of the primordial bovine was discovered, scholars began to question Cumont’s interpretation.  Many began to believe that Cumont had erred in looking for Persian influences, suggesting that these were only superficial and that the bulk of the Cult’s practices drew on ancient Roman traditions.

Mithras, dressed in Persian clothing, stands watching the investiture of Ardashir II (not pictured).  A halo is visible around his head.  He holds what appears to be a sword.  This is Mithras as the Persians imagined him.
4th century carving of Mithra in Taq-e Bostan, Iran. This is the god as the ancient Persians imagined him. © Baharlou/

With skepticism in Cumont’s theories about the Tauroctony increasing, scholars began to look for other explanations.  Many returned to the astrological symbols sometimes depicted in the bull-slaying scene.  Though not in the Tauroctony at San Clemente, a zodiac is often pictured above Mithras as he slays the bull.  This suggested that the meaning of the bull-slaying scene might be found in the stars. 

The Age of Taurus

To the Romans, the night sky was not yet the impersonal, infinite void we know it to be today.  Rather, it was a tapestry encompassing the earth through which gods and mythical beasts communicated their will to mankind.  Symbols found in Mithraic temples suggests followers of the Cult of Mithras embraced these Roman astrological traditions and adapted them to fit their belief system. 

Among the most important constellations to ancient Romans was Taurus, the bull.  It, together with 11 other constellations, form the astrological zodiac.  But Taurus, for a time, held a privileged position even among the other zodiac signs.  This is because from approximately 4400 BC to 2200 BC, during the spring equinox, both the sun and Taurus were located in the same patch of sky. Taurus’s prominent position in the sky during the spring equinox (an auspicious date in many cultures), is why these two millennia are sometimes referred to as the Age of Taurus.

This illustration shows the astronomical zodiac, represented by a ring bearing the signs of the zodiac, encircling the sun and earth.  It illustrates the end of the age of Taurus - with the constellation Aries taking Taurus's position behind the sun (as seen from Earth).
Astronomical depiction of the equatorial zodiac. © Juulijs/

But then something happened.  The position of the stars changed so that during the spring equinox, the sun was no longer in the same position as Taurus.  It had moved to Aries, the Ram.  Had Mithras been responsible for this change? Today, we know that this seeming movement of the constellations is due to the wobbling of the earth, which gives rise to a 26,000 year cycle known as the precession of the equinoxes.  An illustration of this phenomenon can be found, here.  The science behind the precession was of course unknown to the ancients.  To them, the sky was the dominion of the gods.  Thus any change, even if barely perceptible over the course of a single human life, had to have divine origins.  

The Age of Aries

Historian David Ulansey argues the perception among ancient Romans that Mithras was the driving force behind the precession of the equinoxes lied at the core of the Cult’s beliefs.  This is in part validated by the philosopher Porphyry, who, writing in the third to fourth century AD, noted Mithras was assigned a prominent seat along the celestial equator corresponding to the constellation Aries.  This is what the bull-slaying scene is depicting, argues Ulansey.  Mithras is bringing to an end the Age of Taurus and ushering in his own age, the Age of Aries.

As Ulansey notes, such a message would have appealed to ancient Romans, who believed that after death, the soul ascended through a series of heavenly spheres to an afterlife among the stars.  Passing through these spheres was difficult and required secret knowledge and passwords.  Certainly a being able to move the sun from Taurus to Aries would have the power to assure a smooth ascent and therefore make him worthy of worship.  Based on this, Ulansey speculates that the Tauroctony, at its core, is a symbol of the power of Mithras to guarantee an agreeable afterlife.

A colored print of the 19th century Flammarion Engraving.  A man is pictured kneeling near the edge of the earth and reaching through the sky to discover a magnificent realm beyond.  It illustrates how ancient Romans might have imagined the heavenly spheres.
A colored print of the 19th century Flammarion Engraving. The picture illustrates how ancient Romans might have imagined the heavenly spheres. (Houston PhysicistCC BY-SA 4.0)

Looking Further

But is that all there is to it? Did Mithras slay the bull only to demonstrate his power?  The complexity of the Tauroctony suggests there may be further levels of meaning embedded in it.  For instance, some historians speculate that the slaying of the bull is a salvific act.  Like Christ’s sacrifice, this act of Mithras may have symbolized the opening of a new path to spiritual renewal and salvation. Others suggest historians have been too quick to dismiss Cumont’s theories about Persian influences on the Cult of Mithras.  They speculate that further study of ancient Iranian religions will over time help us understand more about the Tauroctony.

This ongoing debate illustrates the degree to which we still haven’t penetrated the deeper meanings of the bull-slaying scene.  This is despite the fact that it was once among the most widespread religious symbols in the Roman world.  Yet unlike the Crucifix or the Roman Eagle, the meaning of this symbol was forgotten.  What exactly did the bull-slaying scene mean to the freed slaves and soldiers who worshipped it? Was it just protection in the afterlife, or was there more? These are the questions at the heart of a mystery two millennia in the making.

Related Content

  1. To read about another ancient mystery, check out my post on the Late Bronze Age collapse, here.
  2. Harmony with astrological observations was not unique to the Cult of Mithras. See my post on Angkor Wat (available here) to see how another culture on the other side of the world incorporated astrological themes into its religious rituals.

Sources/Further Reading

  1. For a summary of David Ulansey’s The Origins of the Mithraic Mysteries: Cosmology and Salvation in the Ancient World – see here.
  2. Translations of the writings of Roman philosopher Porphyry are available here.
  3. For a great overview of the Cult of Mithras, see here and here.
  4. For information about visiting the Basilica di San Clemente, check out it’s website, here.