The Dinas Powys hillfort is an Iron Age hillfort near Dinas Powys, Glamorgan, Wales. It is just one of several thousand hillforts to have been constructed around Great Britain during the British Iron Age, for reasons that are still debatable. The main fort at Dinas Powys was constructed on the northernmost point of the hill in either the third or 2nd century BCE, with two further constructs, known as the Southern Banks, being built further down on the southern end of the hill in the following 1st century BCE. It appears that occupation at the site ceased during the period of Roman Britain, but was re-inhabited by an Early Mediaeval settlement in the 5th century CE, who constructed further additions to the fort. The site was subsequently excavated by a team of archaeologists led by Leslie Alcock from 1954 through to 1958.
The hillfort, which was called the dinas ( or fortress) by Welsh speaking locals, is probably the reason the neighbouring village was named Dinas Powys, and archaeologists excavating the site in the mid 20th century decided to rename the hillfort after the settlement, with excavator Leslie Alcock remarking that "it therefore seemed appropriate by a kind of back-formation to restore the village name to [the fortifications]".
History
Dinas Powys hillfort is located on the eastern end of the Vale of Glamorgan, a county borough at the southernmost tip of Wales that geologically comprises predominantly Lias limestone in the south and Carboniferous limestone in the north. The eastern end in particular "is dissected into flat-topped, steep-sided ridges and hills by deep and narrow river valleys, so that in detail the relief of the south-east Glamorgan is a tangle of minor [landscape] features." The hillfort was constructed on one such of these geographical features, a whale-back hill that is just over a quarter of a mile in length. The fort was built on the northerly tip of the whale-back hill, the highest and narrowest point of the vicinity. It had "no visible defences; but on the west side there is a single bank, on the east two banks, while the southern approach is barred by no fewer than four ramparts." It was located near to the harbour at the estuary of the River Ely, which would have been an important entry point for trade in later prehistory: there is certainly evidence for its use as a harbour in the Early and Middle Bronze Age, several centuries prior to the hillfort's initial construction.
Iron Age and Romano-British periods
Phase One at the Dinas Powys site, which comprised purely of the hillfort on the northernmost tip of the hill, began construction during the Iron Age, at some point in the third or 2nd century BCE. It was evidently settled by a community at this time, as is evidenced by large quantities of Iron Age pottery at the site. There are also several postholes that have been excavated inside the fort, indicating that there may well have been buildings constructed inside of it at this period. Phase Two of Dinas Powys began construction in the Late Iron Age, during the 1st century BCE, and saw the building of the two Southern Banks, which were located on the southern end of the hill, away from the main fort. According to excavator Leslie Alcock, these two defences did not appear to have ever been completed, for instance there was no evidence that a gateway was ever built between them, something which would have meant the banks were of little use in a defensive situation.
Throughout much of the 20th century, archaeologists thought that hillforts were constructed to be defensive structures in a society that was dominated by warfare, or the threat of warfare between different tribal groups. Indeed, excavator Leslie Alcock remarked that the main Dinas Powys fort was "heavily defended", but that the Southern Banks were far less defensible.