The Diocese of Mainz is a diocese of the Catholic church in Germany, historically known in English by its French name of Mayence. It was created in 1802 with the abolition of the old Archbishopric of Mainz. The diocese is suffragan to the Archdiocese of Freiburg. Its district is located in the states of Rhineland-Palatinate and Hesse. The seat of the diocese is in Mainz at the Cathedral dedicated to Saints Martin and Stephen.