Superbly interesting opening of a topic, fra Sothoth! If and when you'll dwell deeper into Lithuanian / Baltic mythology, I would very much like to hear of your findings, conclusions and further topics to continue studying! The close connection of current Lithuanian and Sanskrit language was something I haven't read anything about before.
My overall knowledge of serious occult studies and history is still quite young and superficial, however, especially recent years I've been trying to read (mostly just plain) Baltic and Fennic history and depictions of prehistory - and few common thoughts have started to develop in my mind. These are somewhat intuitive still, and I definitely need to investigate and understand more, nevertheless, I've paid close attention recently to any clues within the following points:
1. I think old (even prehistoric) cultures and people (especially the wealthier part) have been much more interconnected than previously perhaps thought (which affects exchange of thoughts, trade etc.) and probably also moving from place to even a relatively distant place was not uncommon. Few things that makes the aforementioned difficult to analyze is that especially trade routes (lucrative and maybe not most common ones) were very often highly protected secrets - of course nobody wanted extra competition on their industry. And some trade routes are just prehistoric. This of course makes the study of them hard because there's little written remaining historic evidence. Though, I think the items found from graves etc. tell a story of quite ancient and far-fetching "international business and trade", which very probably has had less materialistic outcomes too, like adopting and exchanging (religious) ideas and knowledge. What tells a story about keeping other people off from trade routes are the numerous legends and horror stories of monsters and what not living in some directions and distant lands. Also, if a husband or wife of some historic figure (whether in a rich and known ancient culture or some outskirts land like current-day Lithuania) came from "distant lands" it wasn't always so explicitly written down exactly where the person came from or not considered worth knowing. All in all, this might mean that not only did some ancient Baltics adopt far-traveled ideas, but also distant stories and news, and somewhat "international" currents might have also shaped Indian and other higher cultures, too. So, finding "an original source" might be impossible, and sometimes not even relevant.
2. At least for me, but maybe also more commonly, the current (or 19th century born) nationalistic view also influences how certain kingdoms and cultures are viewed. Often you get the impression that they were much more static (and maybe also more uniform within a certain area) especially with regards to their thoughts and traditions, but also geographically and regarding the overall borders (of influence). Again, it might be that not everyone was cosmopolitan, but my educated guess is that having certain clicks and families might have been enough to upkeep proper in and out flux of things and thoughts at the same time that there were even very differently thinking and acting neighboring folks. ...and certain cities and places have been almost always interconnected, so there have been probably quite strong networks of influential people, for a very long time. Then, with (even medieval) history writing and collection of poems, we have tried to squeeze so much the essence that the heterogeneity of the original people and cultures might have been greatly diluted, which makes also things to look more uniform from distance.
3. Winners write the history, but also preserve their view and might even destroy other views. I know that most forum readers know this very well, but at least I need to remind myself constantly of this when I read history. For example, not surprisingly Church (and Christianized rulers) tried to make Vikings look barbarian, but as importantly Viking rulers were not very keen on praising earlier (more Fennic and Baltic) sea (or river and lake) faring cultures, although adopted some things from them and were definitely mixed etc. So,there are a lot of sediments of deliberate depreciation and forgetting in between. I would also maybe add that especially regarding older Baltic cultures, it is highly likely that the fact that certain noble/wealthy/ruling families since medieval ages kept the (oppressed, previously ruling) ethnic people basically as land slaves, and probably had very little respect or interest in the sediments of their culture. This is probably one of the hardest barriers I've encountered when studying the Baltic (pre-)history. One good example of how the culture of the historian affects the conclusions is that (ancient) Fennic tribes were long time considered to have been so rudimentary that their number system was suspected to be based on number 6 as no larger numbers were supposedly needed. This was fairly common with (German and Swedish) academics even until 1960s or so, however, later it has been proved that obviously our ancestors were very familiar with counting to more than 6 and had a number system based on 10 etc. Somehow similar things still have their influence.
Summarizing my thoughts: I kind of feel that at the same time perhaps similar stories, archetypes, and characters have traveled long distances (sometimes being almost universal) since they resonate so strongly with general human time, character and minds, but also because they kind of resonate with surroundings, meaning they have had enough similar stories to merge with and were shaped to look uniform. Maybe also older traditions were more sponge-like and merging by nature. However this erosion and merging also makes it seem from current viewpoint that there has been a kind of homogeneous, widely-spread, and universal prehistoric religion or source itself, like a direct ancient connection with India and Lithuania/Finland. So, I currently think that all the building blocks may have been much more varied, surviving blocks however not. What academics seem to agree, though, is that the backbones or sources of our oldest stories (like the one with the Devil and the shackles) are at least thousands of years old. Maybe that's also enough time for a story virus to go around the world?
Despite everything I said, I admit that I recently got a proper tickling feeling in my guts when I found really strong similarities with one particular Chinese legend and Finnish Lemminkäinen. So after all, I'm still in many parts just puzzled about pre-historic and even early historic times and things I read...
These were a bit "meta" things considering your topic and opening, but I thought they might be of interest. So, I hope that this doesn't lead to any (suspected) hijacking, since that is not my intention. In addition, I admit that some of the ideas mentioned are fairly common in the scene of "alternative history", which is admittedly based on just a set of educated guesses, but even alternative historians might acknowledge some more subtle signals and elements - even though they often extrapolate other things on them too much. Well, you can blame some academic historians doing exactly the opposite
As of my personal interests in mythological snake-like characters, maybe I should take a look at the Lithuanian dragons, Slibinas...
