Building the stone circles

Although we can only speculate as to the purpose of stone circles, there is one thing we can say for certain - their existence shows, without a shadow of a doubt, that the society responsible for the monuments was sufficiently organised to carry out building projects on a massive scale.

An incredible amount of work went into erecting each stone circle, with recent estimates putting the number of man-hours for the Brodgar and Stenness rings at between 85,000 and 200,000.

This figure shows that the monuments were regarded as significant enough to warrant such an incredible outlay of manpower and time.

Competitive behaviour

According to Professor Colin Richards, who excavated at the Ring of Brodgar in 2008, the idea that one "elite" individual, or group, was responsible for the stone circle's construction can be discounted.

Instead, Professor Richards feels that it was not the completed stone circle that was significant, but rather the physical act of constructing it. The prestige of quarrying, transporting and erecting a fine megalith, he suggested, may have been the driving force behind the development of the monument.

A geological examination of the Brodgar megaliths confirmed that the stones had been brought from different areas across Orkney. These quarries, and the different types of stone obtained from them, may, therefore, represent the different people, or communities, involved in the creation of the stone circle.

The construction, he suggested, might have seen competition between the different prehistoric communities.

"My suggestion is that these communities were quite fiercely competitive. The ring, rather than being this 'harmonious temple structure', that was a joint-effort between different communities, was maybe the site of some really quite competitive behaviour, with the various groups attempting to outdo the other with visible shows of prestige and power.

"Labour, and the deployment of labour, was a visible mark of prestige."

This scenario, said Professor Richards, would see the construction of the ring taking generations — it would have grown slowly as the megaliths were brought in.

"The great feat of labour employed in the digging of the ditch provides some insight into just how important this separation was to Neolithic people. From the excavation, it seems they dug a section of the ditch and then they left it. The colours of rock in the ditch in Trench A have been influenced by water logging, so the orange-brown Orkney flagstones gives way to a deep grey-blue near the base of the ditch. Strangely enough, this actually gives the appearance of water standing in the ditch bottom.

"From this evidence, it is quite clear that in the northern area, at least, standing water collected soon after the ditch was dug. This may seem strange, but it is worth remembering that the surrounding ditch was cut to enclose the area of the stone circle and in the Orcadian island world, water surrounded islands and people. Therefore, the use of water to create a division - to separate it from the rest of the world - was an appropriate strategy employing everyday imagery. They were, I believe, creating an 'island' - a symbolic area representing the world they lived in, and a world they knew.

He added: "But, in terms of architecture, the circle may not have been the most significant point in the landscape. This 'island' has two opposed entrances - probably to enter and exit the circle. The great ring may have been built around a pre-existing pathway and passing through it may have 'altered' a person's state, a bit like entering a church and moving towards the altar. In this case, the end point of the journey may have been further along the Ness of Brodgar."

Selecting and preparing the site

Before we consider the effort required to quarry and transport the stones themselves, we should first look at the preparation of the site.

We can't say for sure what the builders of the Brodgar and Stenness rings were looking for when they set out to find a location for their monuments, but it seems very likely that the chosen sites were significant to them.

The reasoning behind this is simple. There were undoubtedly easier places to erect a stone circle - sites, for example, that did not require the builders to mine through bedrock as part of the construction. The 123-metre diameter ditch that surrounds the Ring of Brodgar, was 7.5 metres deep and is cut from solid rock.

Regarding the Ring of Brodgar, Professor Richards suspects the monument was sited on an existing route across the Ness.

The stone circle has two opposed access causeways - probably to enter and exit the monument. Professor Richards feels that passing through the Ring of Brodgar was just one part of a longer "ceremony" involving the entire Ness of Brodgar.

He said: "The great ring may have been built around a pre-existing pathway and passing through it may have "altered" a person's state, a bit like entering a church and moving towards the altar. In this case, the end point of the journey may have been further along the Ness of Brodgar."

Which came first - the ditch or the stones?

Were the stones erected before or after the ditch? This is an oft-asked question. In truth, we don’t really know.

Over the years, many have assumed the stone must have been first, and then the ditch dug around them. The reason? Efficiency – it would have been easier to move the stones into position and erect them before the massive ditch was dug.

The danger here, however, is assuming that the Neolithic constructors wanted to make things easy. The modern mindset is focused on speed and economy of effort - in other words, what's the easiest and quickest way of getting a job done.

If Professor Richards' theory is correct, and the construction of the stone circle, rather than the completed monument, was important - it could be that the harder the task the more significant the action.

In his paper Rethinking the great stone circles of Northwest Britain, Professor Richards explained: "If a graph was drawn through time of the various estimates of numbers of individuals required to drag or move a forty ton megalith, from Atkinson's initial experiments through to more recent attempts, it would show a steady decrease from 640 to 100. Such preoccupation with efficiency has led to numerous reconstructions, each of which attempts to outstrip earlier efforts in terms of a lower number of people necessary to move and erect a stone circle.

"Clearly, this obsession is linked to western industrial concepts of labour, efficiency and profitability, however, when we turn to ethnographic examples of stone dragging and monumental construction we find this whole line of reasoning totally inappropriate.

"Indeed, the exact opposite frequently applies whereby it is the ability to obtain the largest possible labour force which provides an index of the status of the organising or sponsoring group. Yet again, contemporary ideas and assumptions appear to dictate the way construction and labour are understood within archaeology."

Measuring the circle and quarrying the stones

Once the ditch digging was under way, or complete, work probably began stripping away the turf and vegetation covering the enclosure, ready for the outline of the stone ring to be measured and marked out.

Being a perfect circle, Brodgar would have been relatively easy to mark out, presumably using a single length of rope, pegged at the circle's centre.

Figure 1: Vestrafiold in relation to the Harray and Stenness lochs

Prior to the excavations in 2008, it was suggested that a number of the Brodgar megaliths came from encircling ditch. However, the archaeologists are now certain that could not be the case.

Because of the geology of the site, it is impossible that a complete megalith could have been extracted from the ditch without breaking.

So, if they didn't come from the ditch, where were they quarried?

Geological studies of the megaliths have shown that the stone came from a number of different sites. Of these, only the location of one is certain.

Although there are a number of traditional sites in Sandwick that are thought to have been the sources for the Stenness and Brodgar megaliths, the best known is Vestrafiold, a hill north of the Bay o' Skaill, in Sandwick.

There, prone stones can still be seen lying on the hillside to this day and recent work at the site has confirmed that some of the Brodgar megaliths were indeed quarried there.

Comparatively little effort would have had to have gone into shaping the stones as the Vestrafiold rock splits easily into slabs. After being quarried from the hillside, the megaliths were transported the 7.5 miles to the Ness of Brodgar.

Transporting the megaliths

The two prone megaliths by the side of the Stenness loch, a short distance from the Ring of Brodgar

To haul the stones overland from Vestrafiold to the Ness of Brodgar would also have required considerable manpower and effort.

Again, we cannot say for certain how the freshly-quarried stones were moved, but the Brodgar megaliths were undoubtedly easier to transport than their larger Stenness cousins.

The widespread notion that the megaliths were hauled over wooden rollers is possible - but this might not have been the best way. Aside from the problem of a lack of wood, the method is not particularly efficient over rough or uneven land.

Instead, could it be that some form sled apparatus, possibly using sections of 'track', was employed to drag the stones slowly across the countryside?

A theory that the stones were transported by water, floated down the Stenness loch, was dealt a blow in April 2008, with the results of environmental coring work in the loch.

It showed that prior to around 1500BC, the Stenness loch didn't exist. Instead the area was wet marshy bog, surrounding pools of water or lochans. Not the best landscape to be dragging massive megaliths through.

Erecting the stones

With the momentous task of quarrying and transporting the megaliths complete, the task of erecting on site would probably have been comparatively easy.

The method used by the prehistoric engineers is open to speculation, but it seems likely that a system of platforms, levers, ropes and pulleys were used raise the stones. Systems that continued to be used in the islands for thousands of years afterwards.

Calculations based on size and weight would indicate that the largest stone in the Brodgar ring would have taken around 20 men to raise, with the same number employed to ensure the monolith remained standing.

Given the estimated population at the time, and the close proximity of settlements, scholar Aubrey Burl suggested that a workforce of around 300 labourers would have been available for the construction of Brodgar.

"Working an unlikely unionised eight-hour day with no breaks for weekend, hauliers could have dragged the stones to the site, put them up, dug out the ditch, built up the bank and returned to domestic drudgery within a month."
Aubrey Burl - A Guide to the Stone Circles of Britain, Ireland and Brittany

But although based on solid mathematics, Burl summarises the situation perfectly:

"Mathematically, the computation is immaculate. In terms of prehistoric life, it may be no more than fantasy. And what happened inside the completed arena may rest forever unknown."

Brodgar's ditch and bank