If, like me, you're an American who didn't pay much attention during World History class in grade school, you probably have virtually no idea what "Prussia" was, nor who the "Prussians" were. A couple of years ago I sure didn't.
That neither a land called Prussia, nor a people called the Prussians still exist is certainly one of the reasons for the confusion.
Further clouding the issue is the fact that several different lands and historical governmental entities in central and eastern Europe have been known as Prussia across several different time periods. Correspondingly, multiple different ethnically and culturally distinct peoples have been known as Prussians.
Additionally, I've found it difficult to find sources online that provide a coherent high-level summary of the history of the name, the lands, and the peoples.
What follows is my attempt to fill that gap. A sort of »Preußen für Einsteiger« – that is, Prussia for the uninitiated.
The name stems from a pagan Baltic people – close cousins to the Lithuanians and Latvians – known as Prussians who settled on the southern shores of the Baltic Sea in modern-day Poland sometime after the time of Christ (after the region had been vacated by the east Germanic Goths) and remained in control of the region for about a millenium.
The Prussians probably called themselves something like »Prūsai«. They spoke a language closely related to Lithuanian and Latvian and the other Baltic languages now known as Prussian or Old Prussian.
A German researcher, Dr. Karl Lohmeyer, wrote a history of Prussia in 1881 which included the following regarding the origin of the name:
As for the name »Pruzi« – that is, the Prussians – there have been more than a dozen attempts to explain its origin, but I'll mention here only two.
An old explanation claiming the name stems from »Po-russi« meaning "people living next to the Russ River" or maybe "living next to the Russians" enjoyed nearly full acceptance for a time, but is probably false.
Therefore, we must seek the word's origins in a root word of the Old Prussian language itself.
Of the two root words from the closely-related Latvian language which present themselves as possibilities, one is most likely – the modern Latvian word »protas« meaning "insight", "reason".
Thus, with the Old Prussians, we see the same pattern repeated which we have observed many times with other peoples: The Old Prussians saw themselves as better than the surrounding peoples, more gifted, favored, and perhaps even the only understandable folk.
Coincidentally, there's strong evidence that the origin of the name the Germans gave themselves – »Deutsch« – has essentially the same origin, meaning something like "the only understandable people", providing another example of what the Dr. postulated.
Also note that the later latinization of the word Prussia, »Borussia«, is still used by some famous soccer clubs in Germany such as Borussia Dortmund and Borussia Mönchengladbach. But that stems from a much later time, and I'm getting ahead of myself.
Back to the Old Baltic Prussians on the shores of the Baltic sea during the first millenia…
The most notable and valuable natural resource of this region was, and still is, Amber. In fact, the area is known as the "Amber Coast". We know that the Romans traded for Amber with either the Goths or the Old Prussians because the famous first century latin scholar Tacitus wrote about the Amber Coast his seminal work Germania.
As mentioned, the Old Prussians ruled the region for over a millenia. By around 1200 AD they were known to raid and plunder the early slavic Polish settlements to the south, causing regular problems.
At that time (roughly 1000 AD), the estimated populations of these three european peoples was the following:
After a couple of Polish Catholic priests entered the Prussian lands in an attempt to convert the pagan Prussians to Christianity and returned unsuccessful (sans heads!), the Polish ruler appealed to the Pope in Rome for help taming the Prussian barbarians to the north.
In the early 13th Century the Pope was able to recruit a German enterprise known as the Teutonic Order which began a century-long effort – essentially a European Crusade – to conquer the Baltic Prussians, claim their land, and convert them to Christianity.
Although very long and bloody, this crusade was essentially successful from the German perspective. The Teutonic Order recruited and imported large numbers of German settlers from many different German lands west of the River Elbe ("Germany Proper", so to speak) and established a quasi-sovereign Germanic-ruled state in the east, called the The State of the Teutonic Order, which more or less ruled the region until shortly after the Protestant reformation in 1525.
By the end of the crusade and German resettlement organized by the Teutonic Order, the demographics of Prussia had changed massively. From a region dominated by the pagan Baltic Old Prussians, the land had been forcibly transformed into a majority German region, but with significant Polish and Old Prussian minorities.
About half of the original Baltic Prussian tribe was wiped out during the first century of aggression with the west germanic invaders. But by about 1400, the native Prussian population had recovered to about the same size it had been before the invasion (Boockmann pg 138). The remaning original Baltic Prussians were germanized and integrated both culturally and genetically into the newly-arrived ruling German population, and probably represent a small but significant genetic contribution to modern-day Germans with roots in the former eastern German lands (including my relatives and me according to 23andMe). By the 18th century the Old Prussian language had become fully extinct.
But the Germans also brought their advanced construction and agricultural techniques to the region, building massive castles and fortresses, as well as many beautiful churches, and founding hundres of towns and villages.
The region continued to be known as Prussia even after coming under German control, and the German conquerers essentially adopted the name and, confusingly, also became known as the Prussians. So already, we see the name "Prussian" referring to both Baltic and Germanic peoples. The common factor so far is the land.
Preußen Königlichen Anteils und Herzogtum Preußen
expansion – Brandenburg, Berlin, North Germany