The relations of Royal Prussia and Ducal Prussia with the Polish-Lithuanian state in early modern times were usually described in historiography as German-Polish relations. This automatically placed them in a negative context, primarily after the partition of the Polish-Lithuanian state in the late 18th century. The purpose of this article is to answer the question of how to actually define the relations of the two countries with the Polish-Lithuanian state in the 15th-17th centuries. After the analysis, I decided that when describing the relations between Royal Prussia and Ducal Prussia and the Polish-Lithuanian state in the 16th and 17th centuries, they should be written about exclusively in the context of Prussian-Polish relations, not German-Polish relations. This automatically placed them in a negative context, especially after the partitions of the Polish-Lithuanian state at the end of the 18th century.