The former German Catholic diocese of Kammin[1] (Kamień) existed in Pomerania, from the twelfth century to 1544[2]. In 1549 Martin Weiher was consecrated by the pope, although he was Lutheran. There were Protestant bishops to 1648, (last year of the 30 Years War). It was suppressed, and shortly afterwards its territory was secularised.
Otto of Bamberg around 1130 subdued the area, then the bishopric of Wolin, for the Archbishopric of Bamberg[3]. Otto appointed his disciple Boniface bishop of Julin, creating the first Catholic Pomeranian diocese[4].
Pope Innocent II, by a papal bull of 14 October, 1140, made the church of St. Adalbert at Julin on the Island of Wolin the see of the diocese[5], and Adalbert was consecrated bishop at Rome. There was a conflict between the Archdiocese of Magdeburg and Archdiocese of Gniezno on jurisdiction[6]. The difficulty as to which archdiocese was to be the metropolitan of the new bishopric was in the end evaded by placing it directly under the papal see.
Before 1176 the see was transferred to Kammin (Kamień), where a cathedral chapter was founded for the Cathedral of St. John. [7]