There are at least two ways to explain similarities shared by Mediterranean and Scandinavian traditions. Literary analysis leans heavily on the idea that there was an influence from Classical literature on those who were largely responsible for the documents recording stories about pre-conversion Scandinavia. Folklorists lean heavily on the idea of a common ancestor as well as the possibility of later diffusion or oral traditions. Both factors are likely in play.

Most of what we know about Old Norse traditions and belief systems comes from Christian authors writing a century or more after conversion. That said, conversion in parts of Scandinavia was “thin” at best, and yet it was a factor in how medieval writers recalled traditions before conversion, which coincided more or less with the dawn of the new millennium. Regardless of how clearly those writers were able to “see” what went before, they were literate, and they likely had access to at least some classic literature or were at least feeling its influence second hand.

Not only that, but Biblical influences cannot be ruled out. All this means that Christianized Scandinavian writers were looking at their earlier heritage through a foggy lens at best. This would have tended to exaggerate characteristics in the older tradition that seemed to be echoed in Greek, Roman, or Biblical traditions, drawing accounts of what existed in early Scandinavia more in line with the literary legacy of the Mediterranean.

That explanation can be (and often is) taken too far. Scandinavia was not without its own traditions – beliefs, rituals, and narratives – even before the Greeks and Romans knew how to write – and this was also true after the rise of the literary legacy of the ancient world. Everyone has beliefs and traditions, and Scandinavians were no exception. We may not have a clear idea of the details of that body of folklore, but there is a great deal that we can surmise.

First, there can be little question but that what existed in the far North was descended from the same Indo-European bedrock that influenced Greek and Roman culture. This, then, is a core reason why Greek and Roman deities and Norse deities are similar – a shared common ancestor.

The fact that related Indo-European languages were and are historically spoken from Sanskrit in India to the far flung reaches of the North Atlantic and the far west of the Mediterranean has conjured a great deal of interest. Today, these languages include English, descendants of Latin (for example, Italian, Spanish, and French), German, Scandinavian languages (Norwegian, Swedish, Danish, and Icelandic), Celtic languages (spoken in Ireland, Wales, Scotland, Cornwall, Isle of Man, and Brittany), Slavic languages (Russian, Polish, Serbian, to name a few), Greek, and Indo-Iranian (spoken in Iran and parts of India). Historically, Indo-European languages were even more diffused into Asia. Listing the number of all the members of this language group would take a chapter all by itself.

Coinciding with the distribution of related languages were similar pantheons of early gods together with their stories. This inspired romantics to image a wild period of warriors conquering much of Eurasia, imposing their language and religion on repressed people.

Reality was likely much different. Some Indo-European speakers may have migrated on occasion, but not necessarily in conquest. At other times, languages and mythic traditions may have spread without the movement of people, diffusing through trade networks. We must remember that language, DNA, and folklore are three very different things and that the appearance of one does not necessarily imply the presence of the others.

Scholars have addressed the issue of the distribution of the Indo-European languages and pantheons, arriving initially at the concept of migration, violent or otherwise. This was replaced by the idea of language and myth dispersing even while few people moved. Then scholarship has switched back again. While how people, languages, and stories moved is a fascinating topic, embracing one or the other model to describe what happened will only serve to be challenged by opponents and to be disproven and then proven again in successive waves of academic debate.

Setting aside the question of who may have been migrating, it is possible to consider the distribution of Indo-European pantheons in isolation. A great deal of time has been spent reconstructing both the language and the myths of the Proto-Indo-Europeans. Those efforts represent precise linguistics and ingenious detective work. It can be exciting to explore the folklore of people who died long before any written record. Sadly, the reconstructions of both language and pantheon are idealized. Reality was certainly more complex.

It is extremely difficult to come to grips with how much of a shared Indo-European legacy finds expression in shared characteristics of Mediterranean and Scandinavian myth. Because traditions change over time and as they spread geographically, there is a great deal separating these worlds.

At the same time, we cannot discount the possibility that classical traditions were diffusing north as part of migrating oral tradition, encountering “old cousins” – similar traditions, and blending in. This third avenue may have been a factor that can explain similarities, but untangling the threads that make up the Scandinavian tapestry is a maddening process that is likely not to lead to concrete conclusions. There is, simply, too little evidence to understand much beyond generalities.