EDO4645 - Dorchester Prison, Dorchester; antiquarian observation around 1809

A fragment of a Roman tessellated floor was found during the digging of the foundations for a garden wall belonging to Dorchester Prison in about 1809 (1). The mosaic was part of an E-W corridor with a length of over three metres and a width of 1.4m (10ft by 4.5ft). It was found at a depth of 0.6m (2ft) below the ground. The mosaic is of unusual design and comprised a series of concentric rectangles in blue and white bounded by a band of blue with coarse white borders as shown in a watercolour by the Revd T Rackett, who recorded the find (2). It is possible that it represents a misunderstood swastika-meander (2). A number of coarse and fine tesserae were also found nearby during the construction of the wall. The precise location of this mosaic is not clear. Rackett says that "the wall of the gaol stands within a few feet of the eastern extremity of the Pavement, and other buildings within a garden intercept it towards the west" (1), but no further locational information is given. The Royal Commission suggests its location was at the southwest extremity of the prison grounds, adjacent to the Roman building remains found at Glyde Court in 1880/1966 and probably part of this same building (3). Draper and Chaplin suggest that it was found further to the east in the narrow area between the Prison and the back gardens of the houses on the north side of Colliton Street and perhaps may have been associated with the Roman building remains found at the Prison in 1858 (4). Cosh and Davey suggest it is between the two, but their location places it well to the north. It is likely that the mosaic was found in the narrow area between the prison and the gardens of Colliton Street, as this area best fits the relatively restricted area implied by Rackett's description, but how it relates to the other Roman buildings found in the area is unclear.