The research concerned transformations of soils in the areas of Early-Medieval strongholds and connected differences in floristic composition between forest communities from strongholds and non-synanthropic habitats. The study focused on two areas where Early-Medieval strongholds were situated – Gronowo and Płutowo (Chełmińska Upland, Northern Poland) – surrounded by various types of soils: rusty soils and black earths, respectively. Detailed pedological and floristic-phytosociological investigations were carried out in the sites and their vicinity. Transformations of Tilio-Carpinetum corydaletosumphytocoenoses were performed with respect to the specificity of soils at the settlements and their anthropogenic enrichment in biogenic elements (C, N, P) to a considerable depth.