This study presents a method for decoding the toponymic systems in the area of Slavic-Germanic language contact with the aim of determining where, when, and in which domains the Slavic or Germanic language was used. Subsequently, we confront the linguistic evidence with the evidence from written and archaeological sources.
We discover to what extent language can be a source of ethnicity and whether the pottery traditionally labelled as Slavic can indeed be attributed to the bearers of the Slavic language or groups labelled as Slavs. The outcomes: (1) The toponymic systems in Northeast Bavaria show a relatively late onset of the Slavic language, not earlier than in the second third of the 8th century.
In some places, Slavic speakers joined with the older settlement, where they have left only insignificant toponymic traces, and elsewhere they entered "virgin" areas, where they were the first to name landscape objects. (2) The finds of ceramics, which some researchers have labelled as Slavic and dated to before the second half of the 8th century (ca. 600-750 AD), strikingly overlap geographically with archaic types of German settlement names and with Germanic/Early German hydronyms; by contrast, these areas exclude Slavic hydronyms entirely. We therefore attribute these ceramic finds to Germanic and Early German speakers.
The partial geographic overlap with Slavic settlement names appears to be a later development and of an incidental nature. (3) From the second half of the 8th century onward, the external construction of Slavic ethnicity began to appear in Frankish written sources concerning the Main Basin, and ethnogenic settlement names with /-winden-/ emerged in the areas firmly controlled by Frankish power. At the same time, reliable evidence is lacking for the claim that use of the Slavic language, as we define it today, must necessarily have been a marker of Slavic ethnicity.
The only more-detailed written source available to us indicates that the groups labelled by Frankish elites around 900 AD as being Slavic were linguistically heterogenous. This finding corresponds well with general ideas on the behaviour of populaces in border and migration zones, as well as in areas where power relations have newly stabilized.
In such contexts, new social categories are formed and transformed, and group identities and language are purposefully manipulated. The rise of external ethnifying that occurred in our studied period was related to the consolidation of Carolingian power led by an effort to firmly control the important communication corridor connecting the Rhine and Danube Basins.