"The Diocese of Mainz, historically known in English by its French name of Mayence is a Latin rite of the Catholic church in Germany. It was founded in 304, promoted in 780 to Metropolitan Archbishopric of Mainz and demoted back in 1802 to bishopric. The diocese is suffragan diocese in the ecclesiastical province of the Metropolitan 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. It is the only Roman Catholic diocese in the world – other than Rome – which bears the title of a Holy See." - (en.wikipedia.org 28.12.2019)
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