British Archaeology, no 10, December 1995: Features

Tree rings can show where a wooden object was made. Niels Bonde explains

Count the tree-rings, map the journey

One of the most interesting questions to ask about an archaeological artefact is this: where was it made? If you can tell that a pot, or an axe, or a string of beads found in an excavation were made in some distant place, far from the excavation site, you learn something about contacts between different areas in the past, about the movement of people, or about the exchange or trade of goods.

Now, a new technique has been established for working out the place of origin, or provenance, of objects made of wood. The technique, known as `dendroprovenancing', is connected to dendrochronology (tree-ring dating), and has already been used to shed light on - among other things - the movement of medieval shipping, and on the early post- medieval European timber trade.

In principle the technique is simple to understand. Variation in the annual growth rings of trees is partly dependent on climate, and climate varies from region to region. This makes it possible to build up `master-chronologies' of growth rings, stretching back thousands of years, for individual regions. A wooden artefact need only be tested against various regional chronologies to find the `best fit', and hence its likely place of origin. Over the past few years, a number of chronologies have been established in Europe, and large tracts of the continent are now covered.

In an interesting example of the technique in operation, a Viking longship from Skuldelev near Roskilde in Denmark was tested and found to have come probably from Dublin. The ship, dated by dendrochronology to c 1060-1070, was one of five ships deliberately sunk in c 1100-1150 in the fjord leading to Roskilde - then one of Denmark's major towns - to form a blockade during a period of civil war.

The discovery of the ship's Irish origins was an enormous surprise. The ship is not only the oldest known example of an `Irish' Viking ship, but also the only known example of a Viking longship made in a Viking colony, that had returned, as it were, to the motherland. Nobody knows the historical reasons behind its return; but one theory is that after the Battle of Hastings, the sons of Harold Godwinson, King of England, fled first to Dublin, and from there took ship to seek refuge with their relative, the King of Denmark. It would be charming to imagine that this was the very boat that carried them to safety over the sea.

A second boat analysed by dendroprovenancing seems to have produced the first archaeological evidence for a merchant ship of the Hanseatic League - a powerful trading organisation of free towns that controlled the Baltic in the 14th-16th centuries.

A medieval cog, dated by dendrochronology to 1372, and discovered at Vejby off the coast of North Sj‘lland in Denmark, was found to contain very little cargo - a hoard of coins (mainly English gold nobles), some copper coins, and a few pewter plates. Dendroprovenancing suggests the ship's timbers came from the coastal region of Poland, and that the ship was probably built near Gdansk, in the heart of the Hanseatic area.

The ship appears to have been on its return voyage, having exchanged Baltic raw materials in Britain, and possibly Flanders, for money (and perhaps also for cloth and wine). Interestingly, the records of the Hanseatic League contain references to a ship, on its return voyage, that sank near Vejby in 1377. Although we cannot prove that this is the same boat, the correspondences are exact. The coins on board - which seem to represent a merchant's purse - suggest the boat sank between 1375-1378; and the absence of cargo - accords with the historical record, which states that the cargo was rescued from the shipwreck by Danes and reclaimed by merchants from Gdansk.

A third example of dendroprovenancing has been carried out in Belfast and Sheffield on the origin of oak panels used for panel paintings in the 16th and 17th century. A few years ago, it was generally believed that the timber had come from British or Dutch trees, but the new work shows that a large proportion of the wood in fact came from northern Poland.

This allows us an interesting insight into the medieval timber trade. Wood for panel paintings had to be first-class - it needed to have even tree rings, no knots, and no tendency to warp. Although standard-quality timber - say, for construction - could be found from local sources, it appears that top quality wood had to be sought from further afield.

Dr Niels Bonde is Curator and Dendrochronologist at the National Museum of Denmark

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Heinrich Harke finds new evidence that most native Britons survived

Finding Britons in Anglo-Saxon graves

There can be few peoples whose ethnic origins are so fraught with historical problems as those of the English. Bede, and the Anglo-Saxon Chronicle, provide a story of Anglo-Saxon invasion in the 5th century and large-scale slaughter or displacement of native Britons. Many historians doubt the story - believing many or most Britons survived - but evidence to back up their account has always been hard to find.

Large numbers of native Britons have never yet been recognised in the archaeological record. My own research, however, suggests that evidence for the Britons can in fact be found, and in places where archaeologists have hitherto rarely looked - that is, in Anglo- Saxon settlements and cemeteries. It should not really be a surprise to find them there, as the 7th century laws of King Ine of Wessex contain regulations for Britons, in a way that implies their close co-existence with Anglo-Saxons, often as slaves or serfs. So how do we recognise them? First, we can assume they had fewer grave goods than their Anglo-Saxon masters, and no weapons; and second, we can recognise them through skeletal traits.

Evidence of this sort suggests two distinct phases of interaction between native Britons and Anglo-Saxons - immigration in the 5th/6th centuries resulting in ethnically divided communities and regions; and increased mixing of the two groups in the 7th/8th centuries, leading to the assimilation of the natives into Anglo-Saxon society.

In the first phase, about half the male adults in Anglo-Saxon inhumation cemeteries were buried with weapons; and where there are enough skeletal data, it appears the men with weapons were, on average, one to two inches taller than their weaponless brethren. Other skeletal evidence suggests this was probably not the consequence of different diet and health. There is also strong evidence that the men of post-Roman Germanic populations on the Continent were one to two inches taller than Romano-British men. We may, therefore, accept the stature difference in post-Roman England as evidence that about half the male population in `Anglo-Saxon' communities was of native British stock.

A closer look at individual sites, using this type of evidence, suggests two different patterns of immigration and settlement in southern England. The cemetery of Berinsfield, Oxfordshire, is an example of the `community model' where immigrants had arrived in complete kin-groups, and did not intermarry with Britons despite living close together. In the cemetery, distinct plots contained skeletons with two different genetic patterns, suggesting separate communities of Britons and Anglo-Saxons several generations after the Anglo-Saxon immigration.

The `warband model', on the other hand, is exemplified by the cemetery at Stretton-on- Fosse in Warwickshire, where almost all male burials contained weapons, and where genetic skeletal traits and textile techniques continued from the Romano-British phase to several generations after the Anglo-Saxon immigration. This suggests that an all-male group had settled there and taken native women as wives.

Historical evidence and place-names point in addition to the existence of a third pattern in the south - wholly British enclaves - for instance in the Chilterns and in places such as Walcot and Wallingford (derived from the Old English word wealh for `foreigner', indicating Britons).

This situation changed gradually throughout the 7th and 8th centuries. A drop in average male stature by one inch in `Anglo-Saxon' cemeteries in Wessex suggests that more native groups, previously buried in cemeteries that cannot be identified, were now adopting Anglo-Saxon culture and burial practices. In addition, in existing Anglo-Saxon settlements the disappearance of the stature differential between men with and without weapons suggests more intermarriage between ethnic groups. The appearance of Celtic names in the Wessex royal house (for instance, the 7th century king Ceadwalla) suggests that the elite too became mixed.

In the transition from an ethnically-divided conquest society to an early state, social differences of rank and status were becoming more important than ethnic origins. Biology and culture were moving in opposite directions. The common culture created in the 7th and 8th centuries was Anglo-Saxon, but Anglo-Saxon skeletal traits gradually became submerged in those of the Britons; and together the Anglo-Saxons and Britons became the English.

Dr Heinrich Harke is a Lecturer in Archaeology at the University of Reading

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Numerous ancient diseases can be seen in bone, writes Charlotte Roberts

Never a society that suffered no illness

Disease plays little or no role in most people's perceptions of the distant past. As we imagine bands of hunter-gatherers crossing the landscape in search of prey, we rarely consider whether they suffered from such mundane illnesses as bad backs, arthritic elbows or the common cold.

When we imagine the time when the landscape was first settled, when crops were first raised and field boundaries built, and when Bronze and Iron Age smiths hammered out their splendid metal designs, it often seems beneath our notice - or simply beyond our reach - to wonder about the prevalence of smallpox, tuberculosis and cancer, and the ways in which these and other diseases were treated.

Only for the medieval period, perhaps, does the popular imagination run feverish on the subject of disease. Take any B-movie representation of the period, and every second peasant has a wall-eye or a hunch-back, and hunger and infectious diseases are rife. Whatever the general perceptions and misconceptions about disease and medicine in the past, however, it is a safe bet that illness was at least as common in past societies as it is today, and that in most societies it was both more disabling, and consequently of greater general concern, than it is now.

In order to understand the past fully, we therefore have to understand past illnesses and medicine; and over the last 20 years this field of study - known as palaeopathology - has made great strides in identifying illness in skeletal remains, and has begun to piece together a pattern of ancient health.

Although some ancient mummified bodies are available for study (such as `bog bodies' preserved in peat), most of palaeopathology is conducted on skeletons. It works, in essence, on the principal that many chronic diseases (including bacterial and viral infections) eventually leave their characteristic marks on bone. People who contract a disease and soon die, generally leave no skeletal traces of the disease, whereas those who survive often adapt to the illness through the formation or loss of bone. In this respect it is often individuals with more robust constitutions who provide more evidence for ancient diseases than the weak.

The skeletons of even the most ancient populations are capable of providing evidence of illnesses and medicine, but in practice better skeletal preservation leads to clearer results, and most of palaeopathology's contributions have so far been to the medieval and later periods.

Life in the past has been described as `nasty, brutish, and short', but there is plenty of evidence of the survival of individuals in the past who were deformed or crippled from birth, suggesting some kind of care in the community.

Dwarfs suffering from achondroplasia (`stage dwarf syndrome'), for instance, are known from records and depictions from the Roman and medieval periods (such as in the Bayeux Tapestry), but archaeological evidence for the condition exists as far back as the Late Upper Palaeolithic in Italy, and a single British example from the Neolithic has been tentatively diagnosed.

Club foot has been found at a British Neolithic site at Nether Sewell, and examples of cleft palate and surgically-corrected hare lip are known in Britain from the Anglo-Saxon period. Perhaps more surprisingly, a 10th-11th century child with Down's Syndrome, who seems to have survived to about the age of nine, has been found at Breedon-on-the-Hill, Leicestershire; while a similar example dating from the Late Iron Age, at c 350BC, was found in Germany. Skeletons of people who survived with numerous other types of disabling illnesses are known.

Care is one thing, active medical treatment is another; and palaeopathological evidence for surgery includes amputation of limbs, splinting of fractures and trepanation of the skull. Evidence of amputation is rare - partly perhaps because unhealed amputations could be mistaken for post-mortem breakages of bone - but an early example of successful amputation of half a forearm is known from IX Dynasty Egypt (late 3rd millennium). An unsuccessful British example of lower-leg amputation - of unknown date - was found in Yorkshire, in which a clean-cut end of the femur with a terminal end-saw splinter with no evidence of healing suggested an operative or early post-operative death.

Most fractures found by archaeologists are healed, strongly suggesting a good working knowledge of splinting, and some examples of splints in situ are also known. The earliest, made of bark held together with linen bandages, date from c 5000BC in Egypt; and copper-plate splints have been found on medieval skeletons from York and Reading, as well as elsewhere in Europe. Copper is an effective anti-bacterial agent, and its use in this period suggests some knowledge of its medicinal properties.

The most common operation for which there is evidence in the past is trepanation - the removal of a section of skull. Thousands of examples are known. The operation was especially common in the Neolithic in Europe but it has a worldwide distribution dating from all periods. The evidence for survival is the healing and remodelling of bone around the operation site, and the high survival rate from this high-risk operation attests to the skill of prehistoric surgeons. One Peruvian skull had been trepanned no few than seven times.

The purpose of the operation, however, is unclear, although a superstitious mind might have seen it as a cure for schizophrenia, epilepsy or migraine. Its one modern clinical use is for relieving pressure in the skull following head injury, and ancient trepanned skulls have been found showing evidence of prior head injury. It may, therefore, in some cases have been genuinely effective.

In order to understand the causes of disease in the past, we need to look at the lifestyles and cultural background of ancient peoples - just as a modern GP might ask questions about general lifestyle in order to diagnose an illness today.

Tuberculosis, for instance - recognised by skeletal evidence of osteomyelitis in the hip, knee or spine (as well as, recently, by successful extraction of TB DNA) - is known to be transmitted to humans through infected cattle meat and milk (and thence from person to person). In consequence, one would expect TB to have become prevalent only after the domestication of cattle in the Neolithic period; and indeed American studies have shown that human TB increases as native populations settle and become more dependent on agriculture. The earliest known evidence of human TB was found in Italy, and does indeed date from the Neolithic in the 4th millennium BC.

In the same way, one might expect the prevalence of some environment-related diseases to increase with the growth of urbanism in the Middle Ages, and a recent study of maxillary sinusitis conducted at Bradford University found that a medieval skeletal population from St Helen-on-the-Walls, York, had higher frequencies and more severe sinusitis than a contemporary rural skeletal population from Wharram Percy (see British Archaeology, March 1995). We attributed this to the effects of living in a smoky atmosphere polluted by industrial fumes.

Setting the evidence of illness in its historical context sometimes allows palaeopathology to answer specific historical questions. Syphilis, for instance, was long thought to have been introduced into Europe by Christopher Columbus, following his voyage to Haiti in 1492, as it was unrecorded in Europe before then but spread across the continent from Spain soon after his return. However, the tradition was undermined by the certain diagnosis of syphilis in a female skeleton found in 1992 in the cemetery at Gloucester Friary. Radiocarbon dates were inconclusive, but the skeleton's stratigraphic position suggested a date in the early 15th century, perhaps around 1420.

Although many diseases have been recognised by palaeopathology, there are some common modern diseases that are curiously absent from the archaeological record. We assume, for instance, that osteoporosis - the `silent epidemic' that typically affects post- menopausal women and involves loss of bone mass - was as common in the past as it is today, but differentiating it in skeletons from post-mortem bone decay and skeletal damage is extremely hard.

Similarly, there is little evidence in the past for cancer. Many cancers are associated today with polluting environments and modern diet, and it may be that cancer is principally a disease of the present. On the other hand, it may be that people generally failed to live long enough to develop cancer, or failed to survive long enough once they'd contracted it, for it to leave its marks on bone.

Dr Charlotte Roberts is a Senior Lecturer in Biological Anthropology at the University of Bradford. The Archaeology of Disease, by Charlotte Roberts and Keith Manchester, was published by Alan Sutton last month (UKP25.00).

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