Karl Martell said:
Well, I do find it hard to imagine how a sedentary people (the Germanic people were sedentary) can pick up and leave its homeland, where they have villages, cultivated land, fortresses and all that.
They had fortresses? Where?
I guess I am not as amazed as you are. Perhaps our imaginations are running on different lines. I am guessing when you imagine, say, a Gothic village, you might be projecting a smaller-sized but solidly-built little Medieval villages where generations have lived for eons.
I, on the other hand, imagine old Germanic villages were pretty similar to the kind that can still be found in the African bush south of the Sahara -- sparse, rudimentarily-built, easy to dismantle & disappear without a trace. And I'm also talking sedentary, not nomadic. Sub-Saharan Africa too had massive migrations of sedentary peoples back & forth.
So, no, I'm not shocked. I've seen large patches of nothing where reasonably-sized villages once stood just a few years earlier. Where did they go? War, economics, etc. No trace left? No, nothing at all. (Of course, the African bush has a voracious appetite and eats up abandoned land relatively quickly, but still.)
So, keeping the African analogy in mind, no, I am not surprised at all. Unless they're into building stone monuments or house foundations (which they probably weren't), they're not bound to leave a trace. Or rather, the only trace a tribal nation has of its past are its oral histories. And these oral histories will get erased once they are defeated & enslaved by another.
Keep in mind the only reason we know of the Qadi, Marcomanni, Gepidae, Svebians, Vandals, Alans, etc. is not what they left behind (they left nothing), but simply because they come up in the oral histories of the tribes who defeated them and those victorious tribes lasted long enough (or were close enough to the Empire) for a Roman-educated chronicler set their oral histories to paper.
I suspect the same is true of the Slavs. They too probably have as exciting a history with as much "achievement" as any Germanic tribe. Except they were too far from Rome/defeated too soon to get their stories recorded on time.
I can see half the nation leaving due to famine (as happened in Ireland) but a people in its entirety? It must have taken something drastic, and the old stuff about how Huns running amok in the southern Ukraine caused Vandals along the upper Elbe to pack up and leave doesn't make much sense to me.
Well, during the Mfecane, the Zulus sent many a sedentary African tribe moving wholesale across southern Africa. There are tribes now living as far north as the upper Zambezi & even in the Congo which, not so long ago, lived down around the Orange & Limpopo rivers. If the Zulus can force such large-scale migrations simply by warfare, why not the Huns?
Oh come on! They were not nearly as "dark" as the word "dark ages" implies. Roman civilization continued pretty much as it had before, only the taxes were lower and there was no humongeous government any more. Historians, theologists and poets continued to write Latin chronicles, poems and books like before, the bishops ran their cities like before, and the peasants worked for Latin landholders, like before. They can't have been all that uncivilized, or more would have broken down. It's true that the majority of roads, aquaeducts and palaces decayed as time went by (because no one took care of them) but the invaders had been pretty careful not to tear down too many of them in the first place.
If I exaggerated in one direction, you seem to exaggerate in the other. It was not simply a few aqueducts & roads disappearing.
The Goths had been living in the Ukraine until around 375, which was not exactly in the neighbourhood of any noteworthy civilization. Yet they were able to make themselves lords over Italy, Spain and Aquitaine a hundred years later. The Bavarians and Thuringians may have been no spearheads of civilization (they still aren't, those Ossis and Lederhosen wearers

) but they became Christianized rather quickly and played a role within the Frankish empire. The Moravians also organized themselves into a larger state quickly once the Franks (mostly using Bavarian troops) started encroaching upon their borders.
Well, the Goths couldn't have been very "advanced" if they didn't leave anything behind in the Ukraine (except that itsy-bitsy little principality of Theodoro in the Crimea, obscurely forgotten until the 15th C.)
At any rate, the Ukraine is not
that far. There's a highway betweeen Thrace & Ukraine (it's called the Black Sea

). And remember the Visigoths were Arians before they began moving west. That must mean they must have had subtantial contact with Roman exiles/missionaries while hanging out there.
And what I originally meant was that I found it strange how a people can so quickly seize such a large land as the Slavs did (pretty much everything between Baltic and Aegean Sea) and yet remain so low-profile and hard to trace for a hundred and more years.
Again, not so strange in my mind.