Silbury Hill, situated in Marlborough in Wiltshire, is the largest artificial mound in Europe. Wiltshire. Ever since the Duke of Northumberland sunk the first shaft into the mound’s interior in 1776, archaeologists have tried unsuccessfully to solve the mystery of why the hill was built.
In the early 2000s, the mound’s tunnels were sealed because of subsistence threats. But one final exploration of the hill has revealed new evidence about the mound’s history. While many of these finds are still under analysis, some evidence shows that — whatever its original function — Silbury Hill continued in use until at least the Middle Ages.
Silbury Hill and the Avebury World Heritage Site
Silbury hill is closely associated with Avebury stone circle, 1.4 km to the north and nearby West Kennet Long Barrow. Together all three features form part of the Avebury World Heritage Site.
All three sites are aligned, so they are visible from each other, suggesting that they formed part of a deliberately constructed Neolithic landscape. The significance of their association, however, remains a mystery.
The Construction of Silbury Hill
Silbury hill was constructed in the late Neolithic, between 2500 – 2000 BC. Construction took place over this timeframe in three major phases, with several smaller ones in between.
Measuring 40 metres high and covering 15 acres, Silbury Hill was originally intended to be much smaller. Its first phase of construction involved an initial mound of soil and clay. The second major phase added a layer of rubble chalk quarried nearby around the original core. After a gap of a few hundred years, a further layer of chalk was added, leaving the final monument a gleaming white mound of exposed chalks.
It is estimated to have taken 18 million hours overall to build Silbury Hill, utilising a workforce of over 3000 people. This total resource spread over several centuries, showing that building Silbury Hill would have involved a concerted effort from successive generations of a well-organised community on a project that remained socially significant for centuries.
The Purpose of the Hill
There are various legends and theories about the purpose of Silbury Hill. Some link the site to King Arthur, while others say the devil built the mound to hide treasure. Others believe it to be the last resting place of the mythical King Sil and his horse, although no evidence of any burial has ever been found.
More prosaically, some have speculated that the mound was a reservoir, with the chalk structure acting as a filter for the water. However, it is unlikely that Neolithic communities would have invested so much time and thought into constructing a water tower.
Recent Explorations
In 2000, a cave-in occurred at the summit of the monument close to the site of the original tunnel shaft. It became clear that investigations of the mound’s interior had destabilised the whole structure. As a result, English Heritage, the guardians of the mound, decided to fill in the tunnels with native chalk to help preserve it.
However, before this took place, archaeologists were allowed to make a series of final explorations. And although the mystery of the mound’s purpose was not resolved, archaeologists did discover evidence that suggested Silbury Hill continued to be in use until the medieval period.
While the hill may have been out of use by the Roman invasion of Britain, the Romans may have resurrected the use of the site for religious purposes. The Roman road to Bath runs at the base of the hill, and there is evidence of platforms constructed along the side of the hill. Indeed, archaeologists believe the site could have been used to worship a hybrid Roman British cult.
The hill also seems to have taken on a military function in the Middle Ages. Pottery from the late Saxon/early Norman era was discovered on the mound’s summit, along with evidence of a large building of the same era. It has even been suggested that the mound’s characteristic flat top derives from this period rather than as a part of its original design. Arrowheads dating to the early eleventh century, around the time of the Danish invasions and the Norman conquest, also reinforce the idea of a military outpost on the mound.
Resources
Illustrated Dictionary of Archaeology
Renfrew, C and Bahn, P (1994) Archaeology: Theories, Methods and Practice Thames and Hudson: London
