The Dinas Powys ‘Southern Banks’: excavations of the Ty’n y Coed earthworks 2011–14

The Ty’n-y-Coed earthworks are better known to archaeologists and historians as the Southern Banks at Dinas Powys. These were briefly investigated by Geoff Wainwright in the late 1950s as part of Leslie Alcock’s exploration of the promontory fort known as Dinas Powys. The Southern Banks were central to Alcock’s interpretation of the main defences of the promontory as being a Norman period ringwork built by a native Welsh prince. This interpretation has been shown to be incorrect and the nature of the Southern Banks has become a significant issue for the understanding of Dinas Powys. As part of a reassessment of the Dinas Powys complex excavation and survey were undertaken on the Southern Banks, now named by Cadw and the RCAHMW as the Ty’n-y-Coed earthworks, between 2011 and 2014. Ty’n-y-Coed consists of two separate bank and ditch earthworks (Bank A and Bank B), which appear to be incomplete. The earthworks lie 140m south of the important early medieval promontory fort known as Dinas Powys and were previously trial trenched in the late 1950s. Limited evidence was recovered in the new excavations, but the fieldwork has added significantly to our understanding of the date and function of the earthworks, and their relationship with the adjacent promontory fort. Bank B is interpreted as a univallate L-shaped settlement enclosure occupied during the Late Iron Age and potentially into the early Romano-British period. Sherds of an almost complete Glastonbury Ware bowl were recovered from the primary fill of the ditch, and are likely to represent the deliberate deposition of a significant vessel. The evidence for the date and function of Bank A is considerably weaker, and interpretation more ambiguous. It is suggested that part of the monument appears to be early medieval in date and is tentatively interpreted as an unfinished settlement enclosure.