 Archaeological research has shown that the grod was situated on an artificial hill and had a natural moat formed by the branches of the Słupia, and was protected by a palisade.Records confirm that the area of Słupsk was part of the Polish realm during the reign of Mieszko I and in the 11th century.According to several sources, the first historic reference to Słupsk comes from the year 1015 when the king of Poland Boleslaus I the Brave took over the town, incorporating it into the Polish state.