PART I

This is a complicated question to answer. There were many, many different German communities all over Eastern Europe. The map you linked to doesn’t even cover the full geographic extent of these communities. It excludes, for example, the majority of German enclaves that existed in the Russian Empire, such as the Baltic Germans, the Black Sea Germans, and the Volga Germans.

Some of these communities—like the Baltic Germans, for example—originated in the Middle Ages. Others—like the Volga Germans—were founded as the result of more recent immigration programs sponsored and incentivized by Eastern European rulers. All of this contributed to a centuries-long process of German migration called Ostsiedlung (German for “Eastern Settlement”). This migration process was later recharacterized as a Drang nach Osten (“Drive to the East”), which implied a conscious, collective German push to go East, rather than the former, more neutral term which only indicated settlement and development.

So to try and answer your question, a brief overview is given to each community, starting with the westernmost enclaves and going eastward. This is by no means intended as an exhaustive list of Eastern European German communities, nor even of German communities worldwide, which are even more numerous.

But before we dive into that, let me answer your semi-related question relating to the German language:

It’s important to know that there is no single German language. Instead, there are many different varieties of German, many of them mutually unintelligible with each other. Plattdeutsch, or Low German, is one such German variety; it is almost mutually unintelligible with Hochdeutsch, or High German, which is the standard German variety used between German speakers in Germany, Austria, and Switzerland. The German states therefore constituted a broad linguistic spectrum. Many of these German states—which spoke radically different regional dialects—found themselves connected to each other under the framework of the Holy Roman Empire, and later the German Confederation. It was therefore in their best interests to standardize a common written variety in order to communicate with each other. This was at least partially realized through the writings of Martin Luther:

In much over-simplified form, let us say that Luther familiarized most of the speakers of German with the EMG [East Middle German] written language as a proper medium for communication in print. This was the basis for an inner-language evolution to increase the applicability, flexibility, and range of that language.^(1)

Luther’s variety of written German contributed to the development of a standardized written German. By the 18th Century, the phonology of this written German came to resemble the phonology of North German, thereby standardizing its pronunciation.^(2) From this graphically and phonologically standardized written German, modern Standard High German emerged. The standardization of public education solidified the position of Standard High German as the preferred language of public discourse, and marked the general decline of regional varieties.

Now onto the focus of your question: German settlement in Eastern Europe.

Bohemia and Moravia (present-day Czech Republic)

Ethnic German domination of these regions originated in medieval conflicts between the Moravians and the neighboring Bavarians, Thuringians, and Saxons. In the 9th Century, Moravia was not yet majority-Christian. However, Christian missionaries from Italy, Greece, and several German cities operated within Moravia. The pagan Duke of Moravia not only allowed these missionaries to work within his kingdom, but even allowed his vassal to assist an archbishop in erecting a Christian church in his capital.^(3) The ascension of a new Christian Duke of Moravia—Rastislav—accelerated the Christianization of Moravia, but in a different direction. Rastislav believed that the German missionaries operating in his kingdom were being used by German rulers to exert control over his subjects through the power of religion. In order to balance out the influence of the German missionaries, Rastislav requested that the Byzantine Emperor send him a separate group of missionaries.^(4)

In spite of this, further conflicts with the neighboring German states doomed both Moravia and Bohemia to German vassalage. This near-perpetual vassalage presaged the mass migration of German colonists to Bohemia.^(5) These alien German settlers soon displaced the native Slavs in many local areas, a process the American historian James Westfall Thompson describes at length:

Sometimes a Bohemian village received so many German colonists that it was practically changed into a German settlement, and then even its ancient name was changed. Thus the counts of Bogen, who held much land in the vicinity of the Bohemian Forest, colonized the Czech village of Sušice with so many Germans that its name was changed to Schuttenhofen. When the Teutonic Knights received in 1252 the village of Chomútov (near the Erzgebirge: German—Komotau) they soon Germanised it so completely that a proverb arose: “You can find people everywhere except at Chomútov, where there are Germans. “ Many of these villages were known by two names: thus Teplice was also known as Weckelsdorf, Skalice as Langenau, etc. Some Czech village names were frightfully distorted by this process of Germanisation—for instance, Modlibohov was distorted into the impossible appellation of Nudelbaum.^(6)

The German colony in Prague constituted the wealthiest foreign demographic in medieval Bohemia, and its enormous growth soon made it an immensely important part of the city.^(7) The Germanizing influence of this foreign German colony and others continued for centuries afterward.

The process of Germanization was so potent and so ubiquitous, that by the 19th Century over 50% of all Bohemian and Moravian Czechs had German ancestry.^(8) Over half of the city of Prague was German.^(9) However, the Germans never completely displaced nor completely Germanized the native Slavs. Instead, the idea of a symbiotic Czech-German Gemeinschaft (or community) developed.^(10) A stark economic disparity between the two groups nevertheless remained. The Germans were on the whole wealthier, the Czechs poorer.^(11) Beginning in the 18th and continuing through the 19th Century, the rediscovery and widespread use of the Czech language among the Czech literary elite constituted the Czech National Revival. Economic disparity and a budding national consciousness gradually discredited the idea of a specifically symbiotic relationship.

Degermanization happened with extraordinary swiftness. Prague very rapidly became a majority-Czech city, mostly due to the influx of poor Czechs from the countryside into an industrializing city.^(12) The Sudeten Germans—whose ancestors had settled the perimeter of Bohemia and Moravia—remained, until Czech authorities expelled the whole community shortly after World War II.^(13)

(Continued below)