Palatinate-Simmern was a state of the Holy Roman Empire based around Simmern in modern Rhineland-Palatinate, Germany. Palatinate-Simmern was partitioned from Palatinate-Simmern and Zweibrücken in 1444 by Count Palatine Stephen for his elder son Frederick I. Count Palatine John II (1509 - 1557) introduced the Reformation into Simmern which lead to tensions with the powerful Archbishoprics of Trier and Mainz. John II's son Frederick II inherited the Electorate of the Palatinate in 1559, and gave Simmern to his brothers as Palatinate-Simmern-Sponheim.