Seahenge: a quest for life and death in Bronze Age Britain. Francis Pryor
2700 to 700 BC). The Iron Age was the final prehistoric period, which extended from the close of the Bronze Age to the Roman Conquest of Britain in AD 43. Glyn’s course was known to the university authorities as NBI. Perhaps predictably to the students, it was of ‘No Bloody Interest’. I chose not to study the other option of Iron Age, Roman and Anglo-Saxon, or IRA – which for some reason never seemed to acquire a student name.
I remember being puzzled by archaeologists’ periods. Were Neolithic people aware when they woke up on the first morning of 2700 BC that they were entering the Bronze Age? Of course not. The Ages were invented by some inspired Danish archaeologists, working on museum collections in the last century. They came up with the Three-Age System (Stone followed by Bronze and then Iron) in the first instance simply as a way of ordering their collections. Only later did it gradually acquire a wider significance.
At university we were taught that the Three-Age System would soon be a thing of the past, to be replaced by the flood of radiocarbon dates that were then just beginning to arrive. They have indeed had a profound effect on our understanding of the past, but I can see no consistent evidence that the old Three-Age labels are actually being replaced. I think they’ll be with us for a long time yet.
At Cambridge, British archaeology was taught in a rather rigid framework, or straitjacket, of ‘cultures’. In theory, ‘cultures’ were meant to be synonymous with actual communities of people – tribes or confederations of tribes. But in reality ‘cultures’ were no more and no less than types of pottery. So we were taught about the Beaker Culture or the Grooved Ware Culture, and I have to say I found it extremely difficult to imagine the actual people lurking behind these arcane concepts.
The various ‘cultures’ were accompanied by long lists of sites, where the particular types of pottery which were believed to be characteristic of them were found. The lists were, in turn, accompanied by maps, covered with dots and arrows which purported to show how these people/pots moved around Europe. It was all extremely mystifying, and I remember wondering why on earth these people wanted to move around all the time. It seemed, and indeed it still seems, an odd way to behave.
There was a third lecturer at Cambridge who was to have a very profound influence on my subsequent career, partly because, like me, he is a practical, down-to-earth person. He comes from Canada, where I spent much time during my formative years as a field archaeologist. John Coles is remarkable because he has turned his hand to numerous types and styles of archaeology. His doctoral research was on Scottish Bronze Age metalwork, but he is also, or has been, an authority on experimental archaeology, Scandinavian Bronze Age rock carvings, the Palaeolithic (or Old Stone Age) and wetland archaeology, for which he is perhaps best known.
In the mid and later sixties John was doing far more than his fair share of lectures in the Archaeology Department, and he supervised me in a variety of topics. I don’t think I was a very good pupil towards the end of my time at university, because I couldn’t see that there was a future for me in the subject. Archaeological jobs were extremely scarce, and were invariably snapped up by people with good first-class degrees. I knew I stood little chance against that sort of competition. But John persisted, and somehow he managed to cram sufficient knowledge into my skull to earn me a decent enough honours degree.
I don’t want to be unfair to other lecturers in the department, but John seemed unusual in that his head was not stuck in the clouds for most of the time. He was then working in the peatland of the Somerset Levels, and his lecture slides were not just of disembodied artefacts and distribution maps. Instead, he showed us photographs of people with muddy hands, digging trackways in wet peat, or felling trees with flint axes, or wrestling with hazel wattles while reconstructing prehistoric hurdles. Frankly, his lectures were almost the only thing that kept my flickering flame of interest in the subject alive.
Archaeology in the mid-sixties was superficially calm. Old ideas, such as the pottery-based ‘cultures’, still just managed to hold on, but a tide of new thinking and new scientific techniques was about to rip through the old order. The subject would never be the same again. As has been mentioned, one of the most profound instruments of change was radiocarbon dating. Although I’m now older and wiser, I still find it almost magical that one can take a piece of bone or charcoal, pop it into a machine for a few days and then be told how old it is – to within, say, fifty years. And if you’re lucky enough to have a decent-sized sample (a teacupful of charcoal, say) it will only cost about £200.
Before Willard F. Libby, a chemist at Chicago University, invented radiocarbon dating in 1949, archaeologists researching in remote places (such as Britain) had to work almost blind. If they wanted to date something – let us say a Neolithic stone-built tomb – they had to find similar tombs elsewhere across Europe, until eventually they reached the well-dated world of the eastern Mediterranean. In areas such as the Aegean it was believed that the dates were more secure, because actual written records – such as the famous Linear B script of Crete and Greece – extended back as far as 1400 BC. These dates may well have been more secure, but the problem didn’t lie there. It lay in the chain of false – or perhaps more truly forced – reasoning that linked the eastern Mediterranean to more peripheral areas. Radiocarbon was to expose this ruthlessly.
The idea behind radiocarbon dating is quite straightforward. Libby was researching into cosmic radiation – the process whereby the earth’s outer atmosphere is constantly bombarded by sub-atomic particles. This produces radioactive carbon, known as carbon-14. Carbon-14 is unstable and is constantly breaking down, but at a known and uniform rate: a gramme of carbon-14 will be half broken-down after 5,730 years, three-quarters broken down in twice that time (11,460 years), and so on. Libby’s breakthrough was to link this process to living things, and thence to time itself.
Carbon-14 is present in the earth’s atmosphere – in the air we all breathe – in the form of the gas carbon dioxide. Plants take in carbon dioxide through their leaves, plant-eating animals eat the leaves, and carnivores, in turn, eat the plant-eating animals. So all plants and animals – even vegetarians – absorb carbon-14 while they are alive. As soon as they die they stop taking it in; and, far more importantly for archaeology, the carbon-14 in their bodies – in their bones, their wood or whatever – starts to break down. So by measuring the amounts of carbon-14 in a bone, or piece of charcoal, fragment of cloth or peat, it is possible to estimate its age very accurately.
But there are problems. First of all, cosmic radiation has not been at a uniform rate, as Libby at first believed. Sunspots and solar flares are known to cause sudden upsurges of radiation. Nuclear testing has also filled the atmosphere with unwanted and unquantifiable radiation. As if these problems weren’t enough, the quantities of radiation being measured in radiocarbon laboratories around the world are truly minute, especially in older samples. All this uncertainty means that radiocarbon dates are usually expressed in the form of a range of years, say 1700 to 2000 BC, rather than a single central spot-date like 1850 BC.
There was a period of about ten years after the publication of Libby’s initial idea before any reliable datings became available. Then the pace began to hot up. By the time I was sitting my final exams, in May 1967, the early trickle had already become a flood. Today, radiocarbon dating is a completely routine process, carried out in various parts of the world hundreds of times every day.
Those early radiocarbon dates got me thinking about the prehistoric past in a new way. Perhaps it was the scientific certainty they implied, the fact that radiocarbon doesn’t lie. They seemed to connect us directly to the past, and in a way removed a part of the curtain of mystery which hung between us and them – those shadowy figures of the Neolithic twilight.
The new tide of radiocarbon dates produced some extraordinary results. At first, some of the dates were much earlier than archaeologists had expected. But, being human, they were loath to throw out their old ways of doing things just because some scientists told them their dates were wrong. So they pressed on regardless. Then, as the evidence accumulated around them, some conceded that they had underestimated the true age of the Neolithic and Bronze Ages, and that both periods seemed to have lasted roughly twice as long as was previously believed. All of this they could take: their scheme was basically right, just a bit too young and a bit compressed. They were shortly to be proved wrong.
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