The workshop addresses one of the most controversial issues in contemporary medieval studies, which is the extremely fast expansion of the Slavic language(s) across great parts of Europe in the Early Middle Ages. While traditional scenarios assume unity of language, ethnicity, and material culture, leading alternative models emphasize the active role of material culture, through which ethnic identity was constructed to mobilize linguistically extremely heterogeneous population. The traditionalists explain the spread of the Proto-Slavic language by migrations in the 6th-7th century and associate that with specific material culture and with early mentions of ethnic Slavs in written sources. The alternative hypotheses attribute the same material culture and written references to linguistically and genetically very varied communities and associate the subsequent spread of the Proto-Slavic with its status as an ‘official’ language or ‘koiné’. In other words, early ethnic Slavs did not speak Proto-Slavic, no Slavic ‘Urheimat’ did exist, and Slavic speakers may not have common roots.