Did Rome Adopt the Greek Pantheon?

I was always taught, in school and elsewhere, that the reason Romans and Greeks had such similar gods with seemingly different names was that the Romans had borrowed their gods from the Greeks, or rather, refashioned their existing gods to take on aspects of similar Greek deities, as part of their overall adoption of Greek culture, their gradual Hellenization.  For many reasons that I won't go into, this explanation never satisfied me.

That isn't to say that I thought it was a false statement on its face, because in many ways the statement is true.  Romans did borrow some Greek deities, as well as deities they found in other areas they intended to conquer.  That is a partially valid way of seeing the crossover of Roman and Greek pantheons.  What bothers me about it was that it seems like such an incomplete answer, wrapped up in a nice package so that it easily fits into one of those data centers in the mind, without too much reorganization.  When this kind of explanation is extant, and the subject is of more than passing interest to me, the inadequacies tend to gnaw at me.  Over time, I began to believe that while this explanation had some truth to it, it was in the category of being less than 50% of the real story.  I began to believe that the "adoption" method of religious assimilation might be more accurate around syncretism of peripheral deities that were developed later in Greek culture, and which may have had no counterparts in Roman culture (and vice-versa), but that foundational deities in the Roman and Greek pantheons seem to have come ready-made for intellectual integration, so much so in fact that I suspect that it didn't require a lot of effort or even conscious intent.  I've come to believe that, more often than not, the Romans always had strikingly similar foundational gods to the Greeks, with parallels which were so unmistakable that the borrowings would have happened almost on auto-pilot, rather than by an intentional editing of mythological underpinnings.

In fact, this scenario could not have been the case with only the Greeks.  The story of the Roman conquest of Europe is a story of a people who once saw their deities as unique to Rome being forced to come to terms with the fact that their deities were more of a shared mythology.  The primary members of the pantheons of the European, and in some cases, Asian cultures they conquered, seemed to be images of their own, reflected through a very slightly warped mirror.  By no means was the similarity limited to the gods of the Greeks.

For instance, when Caesar campaigned against and ultimately conquered Gaul, a  group of loosely unified Continental Celtic tribes which inhabited what is today the territory of France, he saw that their gods were so similar to Roman and Greek foundational deities, that he resorted to calling them by Roman names in his written descriptions.  Later on, when Rome under Emprorer Claudius conquered some Insular Celtic tribes, the Welsh and others, living on the main island of Britain, they found that not only were their deities strikingly similar, but even the festivals of those deities were similar to their corresponding deities' festivals, in such details as the time and season of observance, the practices and customs of celebration, and the symbolism and iconography at their center.  As a result, the Romans had no issue at all in reconciling their observances to those of the conquered Celts.  Conquered Celtic tribes similarly seemed entirely comfortable with these merged observances.  Ultimately, very little changed, and even the differences seemed complementary.

For instance, Romans immediately recognized in their dealings with the Greeks that their Spring goddess "Libera" was strikingly similar to the Greek Spring goddess "Persephone", both which had a Spring festival of grain that hovered around the Spring Solstice, both of which were daughters of a very similar goddess of agriculture in both cultures (Greek: Demeter, Roman: Ceres), and both of which were married to the deity of the underworld respective to both cultures (Greek: Hades, Roman: Pluto).  Eventually Romans gave "Libera" a Latin rendering of the Greek name "Perspephone", calling her "Prosperina".  Later, when the Romans conquered the Welsh, they found that a similar goddess existed there named "Eostre", with a similar festival centering around the Spring Solstice, and similar parentage and origins with some variations.  Before long, Romans in Welsh areas were observing the Welsh festival to their own goddess "Libera", and didn't see enough difference to feel that any amount of sacrilege had been involved.  (As an aside, this festival of the goddess "Eostre" is what we today celebrate as "Easter"; in fact, the name "Easter" is a modern derivation from the goddess' name "Eostre").

I am not implying that there were not some important differences in the respective pantheons or between respective deities within the pantheons or even in the practices, but I am implying that the similarities were so striking that the differences were not disruptive to the obvious unity in the minds of both the Romans and their conquered peoples.  We can find so many other such situations throughout the Greek and Roman pantheons that it must have been a great mystery to the Romans at the time they sensed it.  Not to leave the other vassals out, we can find other obvious connections between the Roman pantheon and the Germanic and Norse pantheons.  And the ancient Slavic and Baltic pantheons.  And the known Celtic pantheons.  And even the pantheons of the ancient Persians and the ancient and modern Hindus.  The similarities are too incredible to be coincidence, yet it forces us to ask how such an occurrence as this could be?

Linguistics, which is the scientific study of human language, has actually given us a hint as to how this may have happened.  A few years ago, I began to understand that Linguists have for many years understood that European and some Asian and Middle Eastern cultures were speaking languages that seemed to have evolved from a common root.  The first real connection was made between Greek and of all languages, Sanskrit, the ancient language of the early Vedic peoples who migrated into India and eventually overtook its culture.  These are the people we would today call Indian or Hindu.

Then, other connections were made.  Many European and Asian language families were too similar not to have come from a very ancient root language.  Languages in the Germanic (including English), Celtic, Italic (including Latin, and thus Romantic), Greek, Indian (including Sanskrit and Hindi), Persian (and thus Farsi), Baltic, and Slavic (including Russian) language families had clearly evolved form a similar root.  Even many ancient migratory peoples, such as the Hittites, the Philistines, and the Tocharians, also seemed to have languages which had clearly evolved from this same ancient root language.  Linguists call this ancient language "Proto Indo-European".  So sure are they in their analysis of the similarities between the languages they believe came from this ancient language, that they have been able to reconstruct an impressive amount of that ancient source language's grammar and vocabulary simply by comparing all of the Indo-European languages together, and interpolating the original words and grammar of that language from their similarities.

I honestly believe we can do much the same thing when we analyze the pantheons of cultures that evolved from that original Proto Indo-European culture.  That ancient Proto Indo-European people, which spoke a language from which all Indo-European languages evolved, clearly also had a Proto Indo-European pantheon from which all Indo-European pantheons evolved.  What this means in a nut-shell is that most European cultures, as well as India, Persia (Iran), and many others outside of the geographical confines of Europe, descend possibly genetically but certainly culturally from a single ancient people, a people which at some point was motivated to migrate and settle in various areas.  Once these migrations occurred, separation led to cultural and linguistic evolution, which is effectively why the incredible similarities are also saturated with seemingly inexplicable differences.  I believe that is why there are so many similarities between Roman, Greek, Celtic, and Germanic deities.  And it is why we can see very clear similarities between Roman gods and the gods of both ancient and modern Hindus, and before the advent of Zoroastrianism unified their pantheons into only two deities, the gods of the ancient Persians as well.  It is why what little we know of ancient Baltic and Slavic deities fits right in with the same patterns of similarity.

Let me center on the most prominent example of the ancient heritage I am referring to.  The ancient Hindu Vedas mention a deity that is called "Dyaus Pitr".  Though it's clear that modern Hinduism has demoted him to an ancestral deity (allowing other gods to take his place and his attributes), it's equally clear that this god was once a chief Vedic god, likely even the chief Vedic god.  Compare his name to that of the Greek chief deity Zeus, sometimes referred to as "Zeus Pater", and it should be rather obvious that the Greek name has a similar etymology to the ancient Vedic name. Compare further the name of the Roman chief deity, "Jupiter": "Ju-PIter" sounds very much like a similar name which over time evolved into a different pronunciation.  The original meaning may have even been lost on the Romans, but it seems to demonstrate that the origins of that deity go back a long time, long before Romans would have felt pressure to conquer or integrate with Greece.  Taking a look at the chief Germanic deity, their chief deity was "Odin", a former Germanic chieftain who became deified.  Before "Odin" achieved this place within the Germanic and Norse pantheons, a deity named "Tyr" was the chief deity with the properties that are usually attributed to Zeus, Jupiter, and Dyaus Pitr.  Linguists have long understood that "Tyr" is a linguistic evolution from the same original root that "Dyaus", "Zeus" and the "Ju" in "Jupiter" came from.  Linguists and scholars have essentially reconstructed name for the ancestor of these common deities, and that name is "Dyḗus Pḥatḗr", which in the Proto Indo-European language means "sky father".  The connections are rather clear.

When the Indo-European peoples migrated away from their original territories more than 5000 years ago, they began to spread over the world as we know it.  They migrated to and occupied most of Europe, large parts of Asia, and even the Middle East.  And as the progeny of the Proto Indo-European peoples migrated, the evolving progeny of the Proto Indo-European language and religion began to proliferate the world.  As a result, the various evolutions of the Indo-European Pantheon once represented a significant part of the religious workings of the world.  Basically, Indo-European gods were once served by a significant portion of the human population.  Because the Roman Empire had conquered so many territories, particularly territories populated by adherents to Indo-European religions, and because that Roman Empire had made a seemingly sudden switch to Christianity as the State religion in the Fourth Century A.C.E., Christianity began to replace those religions at a rapid pace.  Later, the rise of Islam in the Eastern provinces also served to displace the Indo-European religions in territories that were originally outside of Western reach.  The result is that today, very few of the practices that evolved from devotion and service to that ancient pantheon are still overtly kept today.  Zoroastrianism has some continual adherence among small populations, and there are those trying to revive Greek, Roman, Celtic, Germanic, and Norse practices, but the numbers are few by comparison to the larger populations. The result is that Hinduism in India is the only spiritual practice of devotion to a child religion of the Indo-European pantheon employed on a large national scale.

Having said all of that, the children of the Indo-European pantheon are still a deeply embedded aspect of European and American cultures.  In English-speaking countries for instance, we name our planets and months after Roman gods, our weekdays after Germanic and Norse gods, our scientific concepts like atomic elements after Greek deities, and many of our stories and fairy tales are from our Celtic, Germanic, Norse, and Greek past.  And even though Christianity now rules the roost of European religious thought, it is clear that it has been heavily syncretized with these past Pagan beliefs and rituals and stories and concepts to the point that it is doubtful that the earliest adherents to what we now refer to as the Christian religion would recognize it.  Most Christian holidays are borrowed from older Indo-European Festivals, such as Christmas and Easter.  Even many well known Christian Saints are essentially derived from Indo-European gods, such as Saint Nicolas and Saint Demetrios, Saint Martin, Saint Lawrence, Saint Ormazd, Saint Venera, Saint Cyrinus, Saint Aphrodite, and many others are generally thought to have been converted to Indo-European deities.  Worship and veneration of Mary and prayer to various Saints dedicated to specific purposes, practices which don't seem to have existed among the earliest Christians, follow clear models of worship from the Indo-European pantheons from which Christian adopters sprang after the Roman Empire adopted the religion.  The point I am making is that the ancient Proto Indo-European religion is still all around us, and it still permeates a great deal of our lives.

I didn't intend to write this post as a thorough analysis of the subject.  I've barely scratched the surface.  I just wanted to introduce the topic, because it's something that has sparked my interest for the last few years.  Just as many linguists have reconstructed some small part of the original Proto Indo-European language from its linguistic antecedents, many scholars of the ancient world have reconstructed some part of the original Proto Indo-European pantheon from its cultural antecedents.  While the usual evolution has caused some of the ancient deities in the Proto Indo-European pantheons to be displaced or modified, by and large the connections are unmistakable.

To answer the question I asked in the title, "Did Rome adopt the Greek pantheon?", isn't impossible, but it certainly isn't as cut and dry as simply ascribing the process to adoption.  Adoption was so fluid an occurrence because of existing similarities which arose from very ancient shared roots.  It was no accident that as Rome conquered Europe and Asia and even parts of Africa and the Middle East, its peoples found so many similarities in the religious pantheons and the religious practices they encountered.  They recognized a kinship of sorts, even as they couldn't quite tell how such a kinship had come about.  But we can at least trace some part of it and understand how that kinship had come about.  Adoption certainly occurred, but the foundation of that adoption was in a shared legacy in a forgotten past, and thus any narrative focusing on adoption as the primary means of the orchestration of religious syncretism between Rome and Greece, and between Rome and its many other vassals, is at best incomplete, and at worst misleading.