The Archdiocese of Bremen (also Archdiocese of Hamburg-Bremen, German: Erzbistum Bremen, not to be confused with the modern Archdiocese of Hamburg, founded in 1994) is a historical Roman Catholic diocese (787–1566/1648) and formed from 1180 to 1648 an ecclesiastical state (continued under other names until 1823), named Prince-Archbishopric of Bremen (German: Erzstift Bremen) within the Holy Roman Empire.
The prince-archbishopric consistea of about a third of the diocesan territory.
The city of Bremen is de facto (since 1186) and de jure (since 1646) no part of the prince-archbishopric but belongs to the archdiocese.
Most of the prince-archbishopric lies rather in the area to the north of the city of Bremen, between the Weser and Elbe rivers.
Even more confusingly, parts of the prince-archbishopric belong in religious respect to the neighboring diocese of Verden, making up 10% of its diocesan territory.Verden itself has a double identity too—as the diocese of Verden and the Prince-Bishopric of Verden (German: Hochstift Verden).
Each prince-bishopric has the status of an Imperial Estate (German: Reichsstand, plural: Reichsstände), each of which sre represented in the Diet (German: Reichstag) of the Holy Roman Empire.
From 1500 on, the Prince-Archbishopric of Bremen belongs to the Saxon Circle (later the Lower Saxon Circle; German: Sächsischer or, later.
Niedersächsischer Kreis), an administrative substructure of the Empire.
The Prince-Bishopric of Verden, on the other hand, belongs to the Lower Rhenish–Westphalian Circle (German: Niederrheinisch-Westfälischer Kreis, colloquially Westphalian Circle) and sends its own representative to the Diet.
Even when the two prince-bishoprics are ruled in personal union, in order to maintain the two seats in the Diet they are never formally united in a real union.
The same is true for the collectively governed Duchies of Bremen and Verden (German: Herzogtümer Bremen und Verden colloquially, but Herzogtum Bremen und Fürstentum Verden formally) which emerge in 1648 from the secularized two prince-bishoprics.
