Monument record 9083 - Early medieval ditch, West Grosvenor Park

<1> L-P Archaeology, 2019, Chester Amphitheatre Environs Research Project (CAER): Interim Archaeological Excavation Report for 2018, R4443 (Client Report). SCH8896.

During training excavations in the western part of Grosvenor Park in 2018 a substantial linear ditch aligned on a roughly north-south axis was identified at the western end of Trench IV. This feature cut the east-west aligned Roman road (CHER 8255) recorded in previous seasons of excavation. The upper fills of the ditch mainly produced Roman pottery and CBM which is likely to be residual; however, pottery dated the medieval period (c.1250) was recovered from the uppermost fill.

<2> L-P Archaeology, 2024, Chester Amphitheatre Environs Research Project (CAER): Interim Archaeological Excavation Report for 2019 (Training), R4806 (Client Report). SCH9679.

During further investigations in Trench IV in the 2019 season of excavation, the substantial N-S, linear ditch (1137) was further investigated. The dimensions of ditch were at least 9.5m long (north-south), 5m wide (east-west) and 1.2m deep. Its profile was fairly flat-bottomed with sides sloping at an angle of roughly 45°. This ditch proved to be a re-cut of an earlier ditch (1150), also a north-south linear, which measured at least 3.65m long (north-south), 1.75m wide (east-west) and 0.85m deep. The full depth of the ditch can be calculated from the top of the adjacent natural subsoil at c.2m. The profile of the ditch was a blunt ‘V’shape. Within the anaerobic conditions of the lower fill of ditch 1150, pieces of roundwood withies were observed, possibly representing a wattle structure which had collapsed in to the ditch. One of these pieces of roundwood was selected for radiocarbon dating and produced a calibrated date of 774-906 cal AD (71.7%) or 916-968 cal AD (23.7%). This lower fill also contained a high proportion of large broken sandstone blocks which may represent tumble from an adjacent structure such as a retaining wall for a rampart. Two bulk samples were also taken from the upper fill and lower fill of ditch (1150) which suggested that sediment was accumulating in the ditch under conditions of periodic flooding rather than permanent submersion, and that the immediate environment was broadly open, with some taller plants and shrubs present. On the western side of ditch [1150] there was a parallel linear cut which had also been truncated by ditch re-cut [1137]. The linear cut measured at least 2.2m long (north-south), 0.49m wide and 0.13m deep and may represent a timber palisade slot along the inner edge of ditch [1150].

Both ditches [1137] and [1150] are too large to represent a simple property boundary, more likely they were defensive in nature. The radiocarbon dating suggests that the earliest ditch began to accumulate debris in the late Saxon period when Chester was part of the kingdom of Mercia but it is uncertain whether it pre-dates the fortification of Chester as a royal burh in AD 907 or not. It seems likely that the ditch is associated with the pre-Norman minster church of St. John and may delimit part of the ‘bishop’s borough’ referred to in the Domesday entry for Chester.