Bischofsturm Hamburg

Description

The Archäologisches Museum Hamburg operates the Außenstelle Bischofsturm (also Bischofsburg), which displays a ring-shaped tower foundation from the 12th century; the outer diameter of the stone circle measures 19 metres. The preserved remains are among the earliest evidence of a stone building in the historic old town.

The site is located at the intersection of Kreuslerstraße and Speersort, close to Hammaburg-Platz and St.-Petri-Kirche. The findspot lies on a geest ridge where the first settlement of Hamburg has been attested; a stone street running here marks the course of an old trade route and is regarded as the city’s oldest thoroughfare.

During excavations for the St.-Petri-Gemeindezentrum in August 1962, stone layers lying below street level came to light. After initial investigations, the remains were for a long time interpreted as the stone house of Archbishop Bezelin-Alebrand mentioned in Adam von Bremen’s chronicle (1074). Further excavations by the Archäologisches Museum Hamburg and finds from the surrounding area led in 2008 to a reassessment: the relics probably date to the 12th century and are more likely part of a fortification. Evidence shows that the tower existed contemporaneously with a ditch in front of it and lay directly behind the Heidenwall; this permits a possible interpretation as a gate complex, such as the Marien- or Schultor.

Structurally, the foundation consists of a circular field of glacial erratics with an outer diameter of 19 metres and an inner diameter of 11 metres; many of the stones measure around one metre or more. On the west side there is a masonry well shaft approximately 4 metres deep and about 4.4 metres in diameter, constructed from fieldstones with diameters of around 50 centimetres.

The exposed foundations are permanently accessible in the newly designed display room of the Außenstelle in the basement of the commercial building St. Petri-Hof. The stone circle is also visible from the street through the glass façade; within the preserved ring area a presentation has been installed that explains the archaeological evidence and conveys the site’s connection to Hamburg’s early urban development.