Solving the Mithraic Mysteries

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Mithraism, one of the most widespread mystery religions of the Roman empire, arose in the Mediterranean world at exactly the same time as Christianity. Each religion held at its core the belief in a god whose powers and domain lay beyond the boundaries of the cosmos. Because both religions began at about the same time and because both shared an ideology of cosmic transcendence, a study of Mithraism may shed vital light on the cultural and spiritual dynamics that led to the rise of Christianity.

Yet solid information about Mithraism is difficult to come by. Like other ancient mystery religions—the Eleusinian mysteries and the mysteries of Isis, for example—the Mithraic cult maintained strict secrecy about its teachings and practices, revealing them only to initiates. As a result of this secrecy, almost no literary evidence about the beliefs of Mithraism has survived.

Archaeologists, however, have uncovered hundreds of Mithraic temples, called mithraea (singular, mithraeum), scattered throughout the Roman Empire, from England in the north and west to Palestine in the south and east.¹ The greatest concentrations have been found in Rome and in those places in the empire (often the most distant frontiers) where Roman soldiers, who made up a major segment of the cult’s membership, were stationed. The remains of these ancient temples and their contents, I believe, hold the key to the secrets of Mithraism.

Mithraea were usually built underground—in imitation of caves. The typical mithraeum was a small rectangular subterranean chamber, about 75 feet long and 30 feet wide, with a vaulted ceiling. In most temples, an aisle ran lengthwise down the center, with a 2- to 3-foot-high stone bench on either side, on which cult members would recline. The average mithraeum could hold 20 to 30 people at a time. In these subterranean temples archaeologists have found an extremely elaborate iconography—carved reliefs, statues and paintings depicting a variety of enigmatic figures and scenes.² This iconography is the primary source of our knowledge about Mithraic beliefs. But because we do not have any written accounts, the ideas expressed in Mithraic art have proven extraordinarily difficult to decipher.

Our earliest literary evidence for the Mithraic mysteries dates to the middle of the first century B.C. The historian Plutarch says that in 67 B.C. a large band of pirates based in Cilicia (a province on the southeastern coast of Asia Minor) were practicing “secret rites” of Mithras.

The earliest physical remains of the cult date from around the first century A.D. At the cult’s height in the third century, mithraea could be found throughout the empire. The cult’s membership was made up especially of Roman soldiers, bureaucrats and merchants. Women were excluded. The cult flourished until the beginning of the fifth century, when Christianity became so powerful that it could effectively eliminate rival religions such as Mithraism.

Most recent scholarship has assumed that 042Mithraism originated in Iran, and that Mithraic iconography must therefore represent ideas drawn from ancient Iranian mythology. The reason for this assumption is that the name of the god worshiped in the cult, Mithras, is a Greek and Latin form of the name of an ancient Iranian god, Mithra. In addition, many Roman authors indicated that the cult was Iranian in origin. At the end of the 19th century, Franz Cumont, the great Belgian historian of ancient religion, published a magisterial two-volume work on the Mithraic mysteries that assumed an Iranian origin of the cult. Cumont’s work immediately became the definitive study of Mithraism.

There were, however, a number of serious problems with Cumont’s assumption. Most significantly, ancient Iran offers no parallel to the iconography of Roman Mithraism. For example, by far the most important icon in the Roman cult is the so-called “tauroctony,” or “bull-slaying” scene. In this scene, Mithras (accompanied by a dog, a snake, a raven and a scorpion) is shown killing a bull; the scene takes place inside a cave like a mithraeum. In every mithraeum this icon was located in the temple’s most important place, at the back of the mithraeum, at the terminus of the aisle; therefore the tauroctony must have been an expression of the central myth of the Roman cult. If the god Mithras of Roman Mithraism was actually the Iranian god Mithra, we should expect to find an Iranian story in which Mithra kills a bull. However, no such Iranian myth exists. In no known Iranian text does Mithra have anything to do with killing a bull.

Franz Cumont had responded to this problem by focusing on an ancient Iranian text in which a bull is indeed killed, but in which the bull-slayer is not Mithra but rather Ahriman, the force of cosmic evil in Iranian religion. Cumont argued that there must have existed a variant of this myth—a variant for which there was, however, no actual evidence—in which the bull-slayer had been transformed from Ahriman to Mithra. It was this purely hypothetical variant on the myth of Ahriman’s killing of a bull that, according to Cumont, lay behind the tauroctony icon of the Roman cult of Mithras.

In the absence of any convincing alternative, Cumont’s explanation satisfied scholars for more than 70 years. However, during the First International Congress of Mithraic Studies, held in Manchester, England, in 1971, Cumont’s theories came under concerted attack. Was it not possible, scholars at the Congress asked, that the Roman cult of Mithras was actually a 046new religion, and that it had simply borrowed the name of an Iranian god to give itself an exotic oriental flavor? If such a scenario seemed plausible, these scholars argued, one could no longer assume without question that the proper way to interpret Mithraism was to find parallels to its elements in ancient Iranian religion. Franz Cumont’s interpretation of the tauroctony as representing an Iranian myth was, then, no longer unquestionable. Thus, in 1971, the meaning of the Mithraic tauroctony suddenly became a mystery once again: If this bull-slaying icon did not represent an ancient Iranian myth, what did it represent?

Shortly after the 1971 Congress, a number of scholars began exploring a radically different explanation of the tauroctony. In the past few years, this explanation has revolutionized the study of the Mithraic mysteries. According to this explanation, the tauroctony is not, as Cumont and his followers claimed, a pictorial representation of an Iranian myth, but is rather something entirely different: an astronomical star map!

This remarkable interpretation of the tauroctony is based on two facts. First, every figure in the standard tauroctony has a parallel in a group of constellations located along a continuous band in the sky: The bull is paralleled by Taurus, the dog by Canis Minor, the snake by Hydra, the raven by Corvus and the scorpion by Scorpio. Second, Mithraic iconography in general is filled with explicit astronomical imagery: The zodiac, planets, sun, moon and stars are often portrayed in Mithraic art.

Further, several ancient authors speak about astronomical subjects in connection with Mithraism. The philosopher Porphyry, for example, writes that the cave depicted in the tauroctony was intended to be “an image of the cosmos.” Given the general presence of astronomical motifs in Mithraic art, the parallel between the tauroctony figures and the constellations is unlikely to be coincidence.

My own research over the past decade has been devoted to discovering why these particular constellations were so important to Mithraism, and how an icon representing them came to form the core of a widespread religious movement in the Roman Empire.

At the time of the Mithraic mysteries, Greco-Roman astronomy was based on a so-called geocentric cosmology, according to which the earth was fixed and immovable at the center of the universe. Everything was thought to revolve around the earth. In this cosmology the universe was imagined as bounded by a great sphere to which the stars, arranged in the various constellations, were attached. So, while we today understand that the earth rotates on its axis once every day, in antiquity it was believed instead that once a day the great sphere of the stars rotated around the earth, spinning on an axis that ran from the sphere’s north pole to its south pole. (For an illustrated explanation of how the ancients understood the cosmos, see the sidebar “Seeing the Heavens Through the Eyes of the Ancients.”)

Today we know that the earth revolves around the sun once a year; in antiquity it was believed that once a year the sun—which the ancients understood as being closer to the earth than the sphere of the stars—traveled around the earth, tracing a great circle in the sky against the background of the constellations. This circle traced by the sun during the course of the year was known as the zodiac—which means “living figures,” a reference to the fact that as the sun moved along the circle of the zodiac it passed in front of 12 constellations represented by animal and human forms.

Because the ancients believed in the existence of the great sphere of the stars, the sphere’s various parts—such as its axis and poles—played a central role in the cosmology of the time. In particular, one important attribute of the sphere of the stars was much better known in antiquity than it is today: its equator, called the celestial equator. Just as the earth’s equator is defined as a circle around the earth equidistant from the north and south poles, so the celestial equator was understood as a circle around the sphere of the stars equidistant from the sphere’s poles.

The circle of the celestial equator was especially important because of the two points where it crosses the circle of the zodiac. These two points are the equinoxes, that is, the places where the sun, in its movement along the zodiac, appears on the first day of spring and on the first day of autumn. Thus the celestial equator was responsible for defining the seasons, and hence had a concrete significance in addition to its abstract astronomical meaning.

The celestial equator was often described in ancient popular literature about the stars. Plato, for example, in his dialogue Timaeus, wrote that when the creator of the universe first formed the cosmos, he shaped its substance in the form of the letter X, representing the intersection of the two celestial circles of the zodiac and the celestial equator. This cross-shaped symbol was often depicted in ancient art to indicate the cosmic sphere. In fact, one of the most famous examples of this motif is a Mithraic stone carving showing the so-called “lion-headed god,” a personification of cosmic power whose image is often found in Mithraic temples, standing on a globe that is marked with a cross representing the two circles of the zodiac and the celestial equator.

One final fact about the celestial equator is crucial: It does not remain fixed, but moves over time. Today we know that this movement, known as the “precession of the equinoxes,” is caused by a wobble in the earth’s rotation on its axis. As a result of this wobble, the celestial equator appears to change its position over the course of thousands of years. This movement is known as the precession of the equinoxes because its most easily observable effect is a change in the positions of the equinoxes, the places where the celestial 047equator crosses the zodiac. The precession causes the equinoxes to move slowly backward along the zodiac, passing through one zodiacal constellation every 2,160 years and through the entire zodiac every 25,920 years. Thus, for example, today the spring equinox is in the constellation of Pisces, but in a few hundred years it will be moving into Aquarius (the so-called “dawning of the Age of Aquarius”). More to our point here, in Greco-Roman times the spring equinox was in the constellation Aries, which it had entered around 2000 B.C.

The precession of the equinoxes provides the key to understanding the Mithraic tauroctony. For the constellations pictured in the standard tauroctony have one thing in common: They all lay on the celestial equator as it was positioned during the epoch immediately preceeding the Greco-Roman “Age of Aries.” During that earlier age, which we may call the “Age of Taurus,” lasting from around 4000 to 2000 B.C., the celestial equator passed through Taurus the Bull (in which the spring equinox occurred during that epoch), Canis Minor the Dog, Hydra the Snake, Corvus the Raven and Scorpio the Scorpion (in which the autumn equinox occurred). These were precisely the constellations represented in the Mithraic tauroctony.

We may go even one step further. During the age of Taurus, when the equinoxes were in Taurus and Scorpio, the two solstices—which are also shifted by the precession—were in Leo the Lion and Aquarius the Waterbearer. It is thus of great interest to note that in certain regions of the Roman empire a pair of symbols was sometimes added to the tauroctony: a lion and a cup. These symbols must represent the constellations Leo and Aquarius, the locations of the solstices during the Age of Taurus.³ Thus all of the figures found in the tauroctony represent constellations that had 050special positions in the sky during the Age of Taurus.

The Mithraic tauroctony, then, was apparently designed as a symbolic representation of the astronomical situation during the Age of Taurus. But how could the tauroctony have come to form the central icon of a powerful cult?

The answer lies in the fact that the precession of the equinoxes was unknown throughout most of antiquity: It was discovered about 128 B.C. by the Greek astronomer Hipparchus. Today we know that the precession is caused by a wobble in the earth’s rotation on its axis. However, Hipparchus, who assumed that the earth was immovable and at the center of the cosmos, could only understand the precession as a movement of the entire cosmic sphere. In other words, Hipparchus’s discovery amounted to the revelation that the entire universe was moving in a way that no one had ever been aware of before.

At the time Hipparchus made his discovery, Mediterranean intellectual and religious life was pervaded by astrological beliefs. It was widely believed that the stars and planets were living gods, and that their movements controlled all aspects of human existence. Most people believed in astral immortality: that is, the idea that after death the human soul ascends through the heavenly spheres to an afterlife in the pure and eternal world of the stars. In time, the celestial ascent of the soul came to be seen as a difficult voyage, requiring secret passwords to be recited at each level of the journey. In such circumstances, Hipparchus’s discovery would have had profound religious implications. A new force had been detected capable of shifting the cosmic sphere: Was it not likely that this new force was a sign of the activity of a new god, a god so powerful that he was capable of moving the entire universe?

Hipparchus’s discovery of the precession made it clear that before the Greco-Roman period (when the spring equinox was in the constellation of Aries the Ram) the spring equinox had been in Taurus the Bull. Thus, an obvious symbol for the precession would have been the death of a bull, symbolizing the end of the “Age of Taurus” brought about by the precession. And if the precession was believed to be caused by a new god, then that god would naturally become the agent of the death of the bull—the “bull-slayer.”

This, I propose, is the origin and nature of Mithras the cosmic bull-slayer. His killing of the bull symbolizes his supreme power, the power to move the entire universe, which he demonstrated by shifting the cosmic sphere in such a way that the spring equinox had moved out of Taurus the Bull.

If this is indeed the meaning of the tauroctony, then we can also easily understand why the other constellations represented in the tauroctony were pictured there. For, as we saw earlier, these are all constellations that had held privileged positions in the sky during the Age of Taurus. Taken together, therefore, they symbolize the earlier cosmic epoch brought to an end by the activity of moving the universe itself.

Given the pervasive influence in the Greco-Roman 051period of astrology and astral immortality, a god possessing such a literally world-shaking power would clearly have been eminently worthy of worship. Since he had control over the cosmos, he would automatically have power over the astrological forces determining life on earth and would also possess the ability to guarantee the soul a safe journey through the celestial spheres after death.

That Mithras was believed to possess precisely such a cosmic power is proven by a number of Mithraic artworks depicting Mithras as having control over the universe in various ways. For example, Mithras is found portrayed in the role of Atlas, bearing on his shoulders, as Atlas traditionally does, the great sphere of the universe. Another example shows a youthful Mithras holding the cosmic sphere in one hand while with his other hand he rotates the circle of the zodiac. A number of tauroctonies symbolize Mithras’s cosmic power by showing him with the starry sky contained beneath his flying cape.

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If Mithras was in fact believed to be capable of moving the entire universe, then he must have been understood as in some sense residing outside of the cosmos.⁴ This idea may help us to understand another very common Mithraic iconographical motif, the “rock-birth” of Mithras. This scene shows Mithras emerging from the top of a roughly spherical or egg-shaped rock, which is usually depicted with a snake entwined around it.

As mentioned previously, the tauroctony depicts the bull-slaying as taking place inside a cave, and the Mithraic temples were built in imitation of caves. But caves are hollows within the rocky earth, which suggests that the rock from which Mithras is born is meant to represent the Mithraic cave as seen from the outside. As we saw earlier, the ancient author Porphyry records the tradition that the Mithraic cave was intended to be “an image of the cosmos.” Of course, the hollow cave would have to be an image of the cosmos as seen from the inside, looking out at the enclosing, cave-like sphere of the stars. But if the cave symbolizes the cosmos as seen from the inside, the rock out of which Mithras is born must be a symbol for the cosmos as seen from the outside. This idea is not as abstract as might first appear, for artistic representations of the cosmos as seen from the outside were very common in antiquity. A famous example is the “Atlas Farnese” statue, showing Atlas bearing on his shoulders the cosmic globe, on which are depicted the constellations as they would appear from an imaginary vantage point outside of the universe.

That the rock from which Mithras is born does indeed represent the cosmos is proven by the snake that entwines it. This image unmistakenly evokes the famous Orphic myth of the snake-entwined “cosmic egg” out of which the universe was formed when the creator-god Phanes emerged from it at the beginning of time. Indeed, the Mithraists themselves explicitly identified Mithras with Phanes, as we know from an inscription found in Rome and from the iconography of a Mithraic monument located in England.

The birth of Mithras from the rock, therefore, would appear to represent the idea that he is in some sense greater than the cosmos. Capable of moving the entire universe, he cannot be contained within the cosmic sphere. He is therefore depicted in the rock-birth as bursting out of the enclosing cave of the universe and establishing his presence in the transcendent space beyond the cosmos.

This imaginary “place beyond the universe” had been described vividly by Plato several centuries before the origins of Mithraism. In his dialogue Phaedrus (247 B.C.) Plato envisions a journey by a soul to the outermost boundary of the cosmos, and then gives us a glimpse of what the soul would see if, for a brief moment, it were able to “look upon the regions without.” “Of that place beyond the heavens,” wrote Plato,

“none of our earthly poets has yet sung, and none shall sing worthily. But this is the manner of it, for assuredly we must be bold to speak what is true, above all when our discourse is upon truth. It is there that true being dwells, without color or shape, that 053cannot be touched; reason alone, the soul’s pilot, can behold it, and all true knowledge is knowledge thereof.”⁵

The awe-inspiring quality of Plato’s vision of what is beyond the outermost boundary of the cosmos also lies behind the appeal of Mithras as a divine being whose proper domain is outside of the universe. As the text from Plato shows, the establishment by ancient astronomers of the sphere of the stars as the absolute boundary of the cosmos only encouraged the human imagination to project itself beyond that boundary in an exhilarating leap into an infinite mystery. There beyond the cosmos dwelled the ultimate divine forces, and Mithras’s ability to move the entire universe made him one with those forces.

In its concern with cosmic transcendence, we can detect a similarity between Mithraism and Christianity. Nowhere is the Christian sense of cosmic transcendence better expressed than in the opening of the earliest gospel, Mark. There, at the beginning of the foundation story of Christianity, we find Jesus, at the moment of his baptism, having a vision of “the heavens torn open.”^a

Just as Mithras is revealed as a being from beyond the universe capable of altering the cosmic spheres, so in Mark do we find Jesus linked with a rupture of the heavens, an opening into the numinous realms beyond the furthest cosmic boundaries. Perhaps, then, the figures of Jesus and Mithras are to some extent both manifestations of a single deep longing in the human spirit for a sense of contact with the ultimate mystery.

Mithraism, one of the most widespread mystery religions of the Roman empire, arose in the Mediterranean world at exactly the same time as Christianity. Each religion held at its core the belief in a god whose powers and domain lay beyond the boundaries of the cosmos. Because both religions began at about the same time and because both shared an ideology of cosmic transcendence, a study of Mithraism may shed vital light on the cultural and spiritual dynamics that led to the rise of Christianity. Yet solid information about Mithraism is difficult to come by. Like other ancient mystery […]