When it comes to research into changes which took place in Poland in the 10th and the first half of the 11th century and the emergence of the Piast dynasty’s state, the presence of an ethnically foreign population, its conditioning and effects have not been fully recognised. The few historiographical sources do not devote much attention to the arrival of foreign tribes; the single mentions typically pertain to the representatives of the elites, especially dynasties. Attempts have been made to analyse the phenomena by means of toponomastics and archaeology. Due to their ambiguity and late source confirmations, the results of toponomastic surveys do not allow to resolve the issue of migrations or displacement from the 10–11th centuries indepe...