The proceedings of the Castella Maris Baltici X conference contain twenty four articles on the castles sited around the Baltic Sea and the Continent. Castella Maris Baltic conferences have been organised in the countries surrounding the Baltic Sea since 1991 and the tenth conference was held in Finland in 2009. The articles in this publication present the new approaches and analysing methods used on the medieval castles of the Baltic region. These methods analyse and consider the everyday life and inhabitants of the castles, environs outside the walls and the restoration and modern uses of these historical sites. The languages of the articles are in English and German.