The term ‘bog body’ usually refers to human remains found in wetland peat deposits, although other mammals have also occasionally been discovered in such deposits.
Peat is formed at varying rates through compaction and accumulation of plant biomass. Depending on the underlying geology, the available nutrients, topography, the water table level, drainage, and precipitation, raised or blanket bogs may be formed. They may be fairly small or extend over a considerable area. The depth of the peat may vary from 30 cm to over 5 m (Brothwell & Gill-Robinson 2002, 122-123).
The bodies (mummies and skeletons) that have been unearthed at such wetland sites are of great relevance as they provide information on the long-term taphonomy of human remains in these environments. They also provide information on a range of traumata and pathological conditions in a series of individuals showing great variation in preservation (Brothwell & Gill-Robinson 2002, 120; Lynnerup 2007, 2010).
Peat has been cut for fuel for centuries. That makes it likely that human remains would have been discovered in bogs over a long period of time. However, it is only in the past two centuries that literacy and interest in such finds have resulted in a growing number of written records about bog bodies. Based on Dieck’s catalogues (1965 and 1986), it was previously stated that the overall number of recorded finds is probably around 2000 (Brothwell & Gill-Robinson 2002, 120; Gill-Robinson 2003, 43). However, critical revision of Dieck’s work has shown that most of the bodies in his paper are fabulated (Van der Sanden & Eisenbeiss 2006, 111-122). The real number of discovered bog bodies and bog skeletons is unknown.
The most famous continental bog mummies have been found in parts of northern Europe, especially Britain and Ireland, Denmark, northern Germany and the north of the Netherlands. They range in date approximately from 500 BC to AD 500 (Lynnerup 2010).
The Drents Museum in Assen, province of Drenthe, the Netherlands, has in its collection several bog bodies, among which are the remains of a body found around sixty years ago. These remains consist of a fairly complete skeleton, large soft tissue parts and even viscera. The body is referred to as ‘Zweeloo Woman’ because it was discovered in what was then the municipality of Zweeloo (now the municipality of Coevorden). Since her discovery she has been the object of several studies. This paper reports current research results obtained by using new techniques, and compares those results with the conclusions of earlier investigations.
1.1 Discoverynext section
On December 5 1951, peat cutters working in a bog known locally as Juffersveen (‘Damsel’s Bog’) discovered a corpse (Van der Sanden 1990a, 70). The Mayor of Zweeloo was informed of this remarkable discovery and he contacted the Biologisch-Archaeologisch Instituut (Institute for Biology and Archaeology) of Groningen University. The following day, professor Dr A.E. van Giffen and his assistant W. van Zeist visited the site. They soon discovered that they were too late to make in-situ observations, the peat cutters having already dug up the human remains. No remains of clothing were observed.
All the archaeologists could do was to collect the bones and soft tissues and study the peat section at the site of the find. The human remains were placed in a large zinc box and taken to Groningen. At the time of discovery, little information was recorded on the findspot of the Zweeloo bog body.
In his daily reports, Van Zeist refers to ‘Juffersveen’ and ‘a small peat bog’, but unfortunately without specifying its size and location.
Thanks to the information provided by the then Mayor Greebe, the site of the former bog was located on a map in 1988 (Van der Sanden, 1990a, 70). It lies in an area known as Aalder Veld, northwest of the village of Aalden (municipality of Coevorden). Recently, members of the local historical society were asked about the location of ‘Juffersveen’ and informed one of us (WVDS) that it lay a little further south than the area indicated by Greebe. On a land-consolidation map they sketched a bog measuring around 400 x 200 m extending on either side of Gebbeveenweg.
Their bog coincides reasonably well with an elongated, NW-SE-oriented bog measuring approximately 350 x 125 m which is indicated on a topographic map from around 1900 (Wieberdink, 1900, sheet 224).
If this is indeed ‘Juffersveen’, and considering that Mayor Greebe indicated the findspot as lying immediately west of Gebbeveenweg, it is likely that the body was buried in the central part of the bog.
The findspot of Zweeloo Woman lies within the boundaries of the village territory (Marke) of Aalden, which dates back to at least the Middle Ages, and probably a long time before then. The eastern boundary is formed by the brook valley of the Aelder Stroom. The Roman-period settlement in which the woman may have lived has not yet been found; it is most likely still hidden beneath the plaggen soil of ‘Aalder Esch’ south of Aalden, where an early medieval cemetery has been excavated. The distance between the bog in which Zweeloo Woman was discovered and her (assumed) settlement is about 2.5-3 km.
1.2 Post-excavation studies (1952-1994)
In 1952 Van Zeist published a short article in German on the bog find. He stated that analyses of the human remains at the Laboratorium voor Anatomie en Embryologie (Laboratory for Anatomy and Embryology) had shown that they represent a female who was approximately 170 cm tall. Unfortunately the name of the anatomist involved is not reported. Nor are there any written reports giving the exact measurements of the long bone segments.
Van Zeist also discussed the pollen diagram, noting a remarkable gap: Subatlantic peat lying directly on top of Boreal peat. He wrote that he took a pollen sample from ‘between the toes of the undamaged foot’. The results of the analysis confirmed the peat cutters’ statement that they had found the body in the lower layer of blackish brown peat. According to Van Zeist this implied that the woman had lived in the first centuries AD.
Van Zeist lastly mentioned that the intestines contained many husks of millet (Panicum miliaceum) - an observation that did not contradict the find’s palynological date. Four years later Van Zeist (1956) published some new information. The woman’s hair had been cut around the time of her death and her body had been deposited in an old turf cutting (which would explain the conspicuous hiatus in the pollen diagram). The time of deposition, he estimated, was after AD 200.
In the following decades no attention was paid to Zweeloo Woman. In 1987, one of the authors (WVDS), at that time curator of archaeology at the Drents Museum, launched a major bog body research project (Van der Sanden 1990). The first and main aim was a totally new analysis of the preserved corpses – Yde Girl, the Weerdinge Men, Zweeloo Woman and several others – and the finds associated with them (Van der Sanden 1990b, 89-90). Many specialists contributed to this project. We summarise the results below.
The physical anthropologist Dr H.T. Uytterschaut of the Laboratory of Anatomy and Embryology of Groningen University analysed and described the remains (Uytterschaut 1990b, 115-117, 122- 123). Due to some confusion resulting from poor documentation by the museum, parts of her conclusions later had to be rectified (explained in Van der Sanden et al. 1991-92). On the basis of the shape of the pelvis and the size of the mastoid process, Uytterschaut confirmed the earlier conclusion that the individual was female. Her age at the time of death was estimated on the basis of various observations. Epiphyseal union in the long bones, pelvis and scapula indicated a minimum age of 25, the morphology of the pubic symphysis pointed to an age of between 30 and 60 and the sutures of the skull implied an age of between 20 and 30. Histological analysis (Uytterschaut 1985) of a thin section of the shaft of the left femur indicated that she died at an age of 34 ± 7 years. All this evidence led to the conclusion that the age at the time of death was probably around 35 years (Uytterschaut 1990b, 117).
The marked differences between some of the bones of the left part of the skeleton and their counterparts on the right side (e.g. the pelvis) caused a lot of discussion, as the observations were not in accordance with any known physical disorder. Post-mortem deformation (pseudopathology) was suggested as the most likely explanation (Uytterschaut 1990c, 132-135). On the basis of the bones of the right side of the body, the individual was estimated to have been around 138 cm tall, but it was simultaneously assumed that this would not be entirely correct due to post-mortem shrinkage (Uytterschaut 1990a, 102). It was also noted that the woman’s hair was cut around the time of her death (Uytterschaut 1990d, 136).
Because of the aforementioned confusion, Dr M. Voortman and his associates of the Laboratorium voor Gerechtelijke Pathologie (now Nederlands Forensisch Instituut / Dutch Forensic Institute) in Rijswijk re-examined the skin in 1993 and identified the vulva and a breast (right side), which is consistent with the result of the sexing of the skeleton.
The other information can be summarised as follows. Zweeloo Woman was probably of blood group O (Connolly 1990, 148) and suffered parasitic infections caused by whipworm (Trichuris) and mawworm (Ascaris) (Paap 1990, 164-166).
Her last meal consisted of a gruel whose main ingredient was coarsely ground common millet (Panicum miliaceum). The presence of a large quantity of blackberry pips (Rubus fruticosus) indicates that she died in late summer/early autumn. In addition, the intestines contained remains of Polygonum lapathifolium (curlytop knotweed/pale smartweed), Polygonum aviculare (knotgrass), Brassica sp. (black mustard or rapeseed), Linum usitatissimum (common flax), Bromus sp. (grass), Triticum sp./Secale sp. (wheat or rye), Hordeum sp. (barley), Avena sp. (oats), a few animal hairs and the wing case of a beetle (Tenebrio obscurus) (Van der Sanden 1990d, 136; Hakbijl 1990, 170-171; Holden 1990, 265-269). Analysis of pollen samples from the intestines confirmed the macroscopic results (Troostheide 1990). No DNA was found in the skin or kidney (Osinga & Buys 1990; Osinga et al. 1992).
Both the skin and the skeleton were radiocarbon dated. The date of the skin is 1835 ± 40 BP (GrN- 15458), that of the skeleton 1940 ± 70 BP (OxA-1727) (Van der Sanden 1990c, 98). The average of the two aforementioned radiocarbon dates is 1861 ± 35 BP (calibrated 2σ: 78-233 cal AD), which means that Zweeloo Woman lived in the Roman period.
In 1994, when consulted by one of us (WVDS), Dr R.W. Stoddard of the Department of Pathological Sciences of Manchester University expressed his doubts about the deformed bones being simply a case of pseudopathology. He closely examined the skeleton, measuring and weighing the bones and subjecting some of them to soft X-rays and tomographic scanning, and came to the conclusion that the asymmetry is indeed a post-mortem development, but the short forearms and lower legs are on the contrary to be classified as a pathological phenomenon (fig. 2).
Figure 2 Zweeloo Woman’s preserved skeleton (a) and skin (b). (c) and (d) show the shortened, bowed forearms and lower legs.
‘The cadaver shows shortening of the forearms and lower legs by about 50% relative to normal, and corresponding low weights of demineralised bones of these parts. Apart from a mild degree of malformation of the radii, the affected bones are short rather than distorted. There is no remaining evidence of nutritional deficit or infectious illness and no other part of the skeleton appears to be affected. The girdles, proximal portions of the limbs, hands and feet show no abnormality of size, though there is evidence of reactive change in the bones of the feet consequent upon the inevitably abnormal gait.
Several conditions can be excluded. This is not a case of hypopituitary dwarfism, since it is not a generalised failure of growth. Similarly, it is not a phocomelic type of dwarfism, since only a specific segment of each limb is involved and the skull is unaffected. The normal hands and feet argue against an effect of the ‘thalidomide-injury’ type, for example following a viral infection. An ‘anti-Marfan’ type of syndrome can also be excluded, since the equivalent segment is involved in each limb and the skull, hands and feet are spared. There is no evidence of nutritional or infectious cause and the localised nature of the abnormality argues against these. The most probable class of disorder in this case is dyschondrosteosis. This develops during later childhood and adolescence, for unknown reasons, producing the type of malformation seen here. The name is purely descriptive and may cover several syndromes. The condition is rare and the origin (or origins) appear to be genetic’ (Stoddart 1995, 9).
The diagnosis was quoted in the volume accompanying the bog body exhibition that was held in Silkeborg, Denmark, in 1996 (Van der Sanden 1996, 140-141).