When it comes to popular media and even consciousness, the Silbury Hill has unfortunately not made so much of a mark as its more famous British counterpart – the Stonehenge. But if we only consider the physical ambit, there are very few European Bronze Age sites that match with the sheer magnificence of this man-made structure. To that end, the mighty Silbury Hill, with its enormous 39.6 m (130 ft) height, is easily the largest man-made prehistoric mound in Europe.
In fact, some historians regard its volumetric size (that covers around 5 acres of the area) to be similar in scope to the smaller Ancient Egyptian Pyramids inside the Giza Necropolis. And interestingly enough, their dates of construction also pertained to a similar time period, with the more than 4,500-years old Silbury Hill believed to be founded in around 2470 BC (whereas the Great Pyramid was completed in around 2560 BC).
A Grand Display of Architectural Skill
Thought to be a part of the complex of Neolithic monuments around Avebury in Wiltshire (a county in South West England), the gargantuan Silbury Hill goes over 130 ft in height, while accounting for 2 hectares (5 acres) in the area – the equivalent of more than four American football fields and an incredible base diameter of 167 m (548 ft).
Now considering that such an impressive feat was achieved 4,500 years ago with the aid of just rudimentary tools, archaeologists have suggested that such a structure would have taken around 18 million man-hours (the equivalent of 500 men working for 15 years) to complete. And, just to give an idea of this enormous volumetric scope, if the Silbury Hill was placed in London, it would have almost filled the entire Trafalgar Square, while reaching three-quarters of the height of Nelson’s column.
Since we have brought up the sheer scale of the structure, this man-made prehistoric mound is largely composed of chalk and clay that were excavated from the surrounding areas. Once again according to modern-day estimations, the gargantuan size of the mound corresponds to an astronomical 248,000 cubic m (8.75 million cu ft) of earth stacked on top of a natural hill – which was then shaped with precise geometrical considerations, thus resulting in a giant flat-topped cone.
This flat summit of the ‘hill’ is around 30 m (100 ft) wide. But by recent assessment, the plane nature of the crown was probably the defensive handiwork of latter-day Anglo Saxons in the middle ages (as opposed to the pre-historic people who actually constructed the Silbury Hill). To that end, archaeologists estimate that the crown of this mound was originally more bulbous in shape, so as to conform to the circular geometry of the overall scope (including the almost perfect circular base of the hill – which measures an astounding 548 ft in diameter).
Now, in terms of the conceiving of this massive project, the Silbury Hill is believed to have been constructed over two major phases (though many experts – mainly from the English Heritage, believe the current mound went through fifteen cycles of development and was achieved over a period of three generations from 2400-2300 BC). In any case, the initial phase of construction corresponds to a roughly stacked mound with a gravel core that was further supported by the curb of stakes and sarsen boulders.
Chalk rubble and earth were then deposited to give the hill its starting shape. The next phase entailed the further stacking of chalk portions on top of this ‘structure’ that were excavated from the proximate areas. This taxing process involved a step-by-step scope where each layer (of the hill) was being filled with packed chalk and then smoothed off – thus resulting in the significant enlargement and improved geometry of the overall Silbury Hill.
A Mystery As Old As The Stonehenge
Now, while recent scientific assessments have more or less uncovered the structural details of Silbury Hill, historians are still perplexed about the exact purpose of so large an endeavor achieved in the Neolithic Age. One of the means of deducing any such ‘functionality’ of old structures is often analyzed from archaeological pieces of evidence found in the site – but even such methods have almost come to naught in the case of the prehistoric mound.
In fact, the first major excavation project was undertaken way back in October of 1776, when the Duke of Northumberland and Colonel Edward Drax employed a group of Cornish miners to sink a vertical shaft from the top. This was followed by another major endeavor when a tunnel was dug from the edge of the hill’s base into the center of the mound in 1849.
And, the last of the big-scale archaeological endeavors (along with numerous smaller ones starting from the 17th century) was conducted in 1968-70 when professor Richard Atkinson headed the digging project of another tunnel into the central part of Silbury Hill. All of these excavation projects only led to the finding of certain natural items inside the hill, including – clay, flints, turf, moss, topsoil, gravel, freshwater shells, mistletoe, oak, hazel, sarsen stones, ox bones, and antler tines.
Now, according to a recently published work by English Heritage, the purpose of the Silbury Hill might not have entailed anything grand or extraordinary at all. Dr. Jim Leary, an English Heritage archaeologist put forth his hypothesis regarding how the original builders probably started constructing the mound as part of a ‘continuous storytelling ritual’. He further explained –
Most interpretations of Silbury Hill have, up to now, concentrated on its monumental size and its final shape. It has generally been thought to be a concerted effort of generations of people building something out of a common vision and spiritual zeal akin to that spurred the creation of soaring medieval cathedrals. The flat top, especially, was often seen to be a “platform” deliberately built to bring people closer to the skies. But new evidence is increasing telling us that our Neolithic ancestors display an almost obsessive desire to constantly change the monument – to rearrange, tweak and adjust it. It’s as if the final form of the Hill did not matter – it was the construction process that was important.
In essence, the Silbury Hill was possibly a ‘conscientious’ endeavor devoid of any boastful demonstration usually associated with massive man-made structures. Instead, the enigmatic mound might have espoused the societal effort of the builders, who could have passed their techniques and skills for generations – so as to endow the Neolithic hill with its ‘dynamic’ architectural scope.
This fascinating scope of ‘sharing of ideas’ could have gone beyond just the physical limit of the structure itself. Simply put, the location of the Silbury Hill, along with its internal arrangement and layering of certain materials (like antler picks, gravel, chalk, and stones), might have played a symbolic role that was intangibly significant to the original builders.
Legends and Alternate Theories
While the exact purpose of such a gigantic achievement is still shrouded in mystery, there has been no dearth of legends surrounding the Neolithic mound. As a matter of fact, the very name Silbury Hill comes from the legendary King Sil who was ‘supposedly’ buried deep inside the mound while still being perched on the back of his horse. As legends morphed into folklore, the king’s mount became a golden horse along with a life-like gold statue of the king himself.
However, beyond legends and folklore, there are other theories put forth by eminent experts concerning the purpose and its position in the historical context. For example, Professor John C. Barret made his hypothesis that the elevated nature of the mound was an intentional engineering aspect, with the top of the hill signifying the elite position of a few individuals within the Neolithic British society. In that regard, the man-made summit may have accommodated a priestly class who ritually showcased their power and authority by being visible from all the land around when ascending the hilltop.
On the other hand, writer and prehistorian Michael Dames, has put forward his theory that encompasses the seasonal rituals associated with Silbury Hill (and its connected sites, including the Avebury Henge and the West Kennet Long Barrow). Such credible hypotheses also go along with the more sensational ones, including the labeling of the man-made as a huge astronomical calculator or even a symbolic representation of the mother goddess.
However, in any case, one factor remains certain – the enigmatic Silbury Hill was built to endure through the ages, as is evident from the painstaking endeavor of constructing retaining walls of chalk that silently hold the enormous masses of filled rubble in place.
Book Reference: The World’s Most Mysterious Places (Reader’s Digest)