The archaeological site and feature

The mass grave was discovered in 2013 during archaeological excavations prior to housing development in the southern outskirts of Halberstadt, a town located just north of the Harz mountains in the German state of Saxony-Anhalt (Supplementary Fig. 1). This part of the Halberstadt area, called “Sonntagsfeld”, is rich in archaeological remains from various periods and has been settled since the Early Neolithic; traces of six LBK longhouses have previously been identified here32. In the same area, at least 38 regular LBK inhumation burials have been excavated so far, which relate spatially mainly to the houses and therefore are examples of settlement burials. Overall, these graves represent a carefully deployed LBK burial site including subadults and adults of both sexes32, 33.

The mass grave was located in the southeastern part of the currently known LBK settlement area at the site. As most other features there, the mass grave pit was partially disturbed by later (pre)historic activities. This made it difficult to precisely define the edges of the actual feature (Fig. 1), which likely had a diameter of about two metres. Apart from the human skeletal remains, the pit contained few other finds, mainly small pottery fragments, some of which show typical LBK ornamentation. These fragmentary finds are interpreted as settlement refuse that accidentally became part of the infill. The individuals in the mass grave were not equipped with durable grave goods. Their body positions differed widely between prone and supine, extended, crouched and irregular with no pattern apparent. All this is in stark contrast to regular LBK burials, including those from the same site32, but is very similar to the other LBK mass graves12. Six radiocarbon samples of human bone give an overall dating range of 5289–4856 cal bc, which can be refined to 5214–4911 cal bc and probably even to 5080–4997 cal bc, confirming the attribution of the mass grave to the late LBK. This dating range also demonstrates chronological overlap with the nearby settlement, which contains both earlier and later inhumations (Supplementary Table 1; Supplementary Figs 2 and 3).

Fig. 1 The mass grave feature in situ. Individual skeletons have been coloured and numbered for better visual differentiation Full size image

Demography

The pit contained nine individuals, seven of them diagnosed as male (78%). The remaining two are a probable male (11%) and a probable female (11%). The youngest male was ca. 16–20 years old, the probable female ca. 21–26 years (Table 1). Although still subadult in biological terms, as epiphyseal fusion was not complete, the youngest male could have been a social adult in Neolithic society34. The remaining seven individuals all fall between 25 and 40 years of age. This highly peculiar, almost exclusively adult male demography (89%) deviates significantly from that of the nearby settlement burial site32, 33, which shows the standard demography of almost equal numbers of male and female and adult and subadult individuals (Fisher’s Exact Test; sex: p = 0.04; age: p = 0.03). The absence of children from the Halberstadt mass grave is especially noteworthy, as these usually are numerous in the regular individual and irregular mass burial sites, as well as in other non-standard deposition types12, 13, 24, 35. For example, both massacre mass graves of Talheim and Kilianstädten have balanced ratios of subadults to adults from which the Halberstadt mass grave significantly differs (Fisher’s Exact Test; p = 0.04 and p = 0.05, respectively). The difference to the child-dominated mass grave of Wiederstedt is even more obvious (Fisher’s Exact Test; p = 0.00). In contrast, the encountered sex ratio with a pronounced lack of females is reminiscent of the massacre sites of Asparn/Schletz and Kilianstädten23, 24. But overall, the mass grave of Halberstadt clearly represents a population sample different from all other attritional or catastrophic LBK burial assemblages known so far. The clear dominance of younger adult males and the absence of children have to be especially stressed, as these characteristics, in combination, indicate important contextual differences from the other sites of LBK mass burial and/or collective lethal violence.

Table 1 Osteological characteristics of the individuals found in the mass grave Full size table

Palaeopathology

The analysis revealed perimortem blunt force cranial injuries as the most numerous lesions in the assemblage (Fig. 2). All seven individuals with extant cranial remains show at least one perimortem cranial trauma (Table 1). Individuals 5 to 8 have one cranial injury, ind. 9 likely suffered two, and ind. 4 shows at least five or, more likely, six separate traumata. As the skeletal remains are incompletely preserved, it is possible that more injuries had originally been present. Also, due to the fragmentary and fragile condition of some of the bones, cranial trauma has initially been subdivided into securely identified perimortem trauma (9, 69%) and likely perimortem trauma (4, 31%). All instances of the latter are found in ind. 4, who also shows two securely identified perimortem cranial fractures. The recognised injuries as a whole are almost exclusively located in the posterior half of the skull (12, 92%), affecting the posterior parts of the parietal (7, 54%) and the superior parts of the occipital bones (5, 38%) (Fig. 3). Only one perimortem trauma is found on a frontal bone (1, 8%). This injury is again found in ind. 4 and represents one of the securely identified fractures. The locations of the likely injury zones of ind. 4, the most traumatised individual in the sample, are within the same areas as in all other individuals, thereby supporting the overall pattern. Therefore, both trauma categories are pooled again for all further discussion. More injuries are found on the right side (8.5, 65%) than on the left side of the cranium (4.5, 35%), which is also the case at Talheim and Asparn20,21,22. Due to incomplete preservation of fracture margins and missing bone fragments, size and shape could not be precisely determined for all traumatic lesions, but at least two of the best preserved traumata appear very similar in their dimensions (Fig. 2d–f). Both are roughly triangular in shape and are located in the horizontal midline of the occipital bone slightly above the external occipital protuberance and the superior nuchal line. The fracture in ind. 7 is slightly to the left of the median plane and measures ca. 23.4 × 16.8 mm; the fracture in ind. 9 is slightly to the right of the same plane and measures ca. 24.4 × 17.7 mm. Several other fractures with incompletely preserved margins located in the occipital bone appear to have been of roughly similar sizes, measuring between ca. 19.4 and 21.4 mm in one of their dimensions. In general, the identified cranial injuries show the known characteristics of perimortem blunt force trauma, with internal bevelling, concentric and radiating fracture lines, and depressed external fracture margins36.

Fig. 2 Examples of cranial perimortem blunt force trauma identified in the mass grave. a Trauma in the right half of the frontal bone in ind. 4. b Trauma in the left parietal bone of ind. 9. c Trauma in the midline of the occipital bone (near bregma) in ind. 5. d Trauma in the left half of the occipital bone of ind. 7. e, f Trauma in the right half of the occipital bone in ind. 9. Panels a–e in ectocranial view; panel f in endocranial view. Scale bar length is 2 cm Full size image

Fig. 3 Compilation of the approximate locations of cranial trauma. Signature size represents general trauma size (large vs. small), darker shading represents securely identified trauma, lighter shading represents likely trauma. Signature locations indicate approximate points of initial impact. Numbers indicate the affected individuals with skulls preserved (ind. 2; inds 4–9) Full size image

In addition, at least three major limb bones of three different individuals show perimortem fractures. The right femur of ind. 7 (Fig. 4a) and the left humerus of ind. 8 are fractured about mid-shaft. The right humerus of ind. 6 has a fracture in the distal third of its shaft (Fig. 4b). All three fractures are complete. Two likely cases of similar fractures are present in one fibula fragment and one forearm bone fragment, both of which had been collected as loose finds from the mass grave prior to the block-lift. One further perimortem trauma has been identified in two neighbouring left ribs in ind. 8. In contrast to all other injuries, these lesions resulted from sharp force trauma and seem to have been caused by a single cut orientated vertically to the axis of the affected bones (Fig. 4c). Besides the perimortem traumata, very few other pathological conditions could be identified, none of which seem to be related to the specific burial context under consideration here. These lesions consist of isolated Schmorl’s nodes in the vertebral column of ind. 2, healed avulsion injuries of lumbar vertebrae 3 and 4 in ind. 8, and a single caries lesion of the lower right first molar in ind. 9.

Fig. 4 Examples of postcranial perimortem trauma identified in the mass grave. a Shaft fracture of the right femur in ind. 7. b Shaft fracture of the right humerus in ind. 6. c Cutmarks in two left ribs in ind. 8. Scale bar length is 2 cm Full size image

Taphonomy

The bodies appear to have been dumped into the pit without care for their individual positions, which differ from those encountered in carefully arranged LBK burials14, 15. The spread of the corpses followed the outline of the pit, the limbs apparently remained as they had fallen. This is exemplified most clearly by the aberrant positions of the perimortem fractured arm and leg bones of two of the individuals (Fig. 5). The complete fractures of the shafts acted like additional joints in these cases which resulted in ca. 90° angles between the fracture ends. Their spatial relations also indicate that, although complete osteological discontinuity occurred, soft tissue connections were still in place. In the right femur of ind. 7, the distance between both fracture ends implies that these soft tissue connections were not wholly complete anymore, allowing the proximal end of the distal part of the limb to rotate away from the distal end of the proximal part upon deposition, while still remaining partly attached.

Fig. 5 Examples of aberrant positioning of perimortem fractured limbs. In situ positions of the perimortem fractured right upper limb in ind. 6 (humerus; yellow) and right lower limb in ind. 7 (femur; red) Full size image

Upon excavation, several major skeletal elements were already missing (Fig. 1). These include the complete skulls of inds. 1 and 3, and most of the skull of ind. 2. The upper half of the body of ind. 1 is absent, as well as its left lower leg bones. Ind. 2 is missing the bones of its right leg and most parts of the left lower leg, while the proximal part of the left tibia is still present and articulated. Ind. 4 is missing the left leg bones, ind. 5 the right lower leg bones, ind. 6 the left leg bones including the left pelvic bone and sacrum, ind. 8 the bones of both forearms, the left femur and all right leg bones. In ind. 9, all bones distal to the fifth cervical vertebra are absent. There is a possibility that the remains labelled ind. 1 and ind. 9 are actually part of the same individual, but the distance between these partially preserved remains and their different orientation rather suggest that they belong to different individuals, as all other major body parts actually present in the feature were still articulated upon deposition.

Many smaller elements, especially of the hands and feet, but also cranial fragments, ribs and vertebrae, are missing as well. These elements have most likely been displaced and removed over time by small burrowing animals. Evidence for rodent activity is manifold, and includes smaller bones and pottery fragments scattered throughout the feature. Infilled rodent tunnels were observed entering the mass grave in different places, rodent skeletal remains were found within the grave fill and several human bones show clear traces of rodent gnawing37 (Fig. 6a). Bone damage typical for perimortem carnivore gnawing activity is evident in several individuals37 (Fig. 6b, c; Table 1), and is securely identified in skeletal elements along the north-western edge of the mass grave feature. All affected bones are elements of limbs that are missing their distal parts, for example the left tibia of ind. 2 or the right femur of ind. 5. Both of these gnawed bone ends came to rest right at the edge of the feature in the same spot. It is highly likely that the parts missing distal to securely identified carnivore gnawing traces have been removed by these animals. In cases where no carnivore damage was observed, animals might have been responsible for missing bones as well, but later human activity might also have accidentally removed these elements over the millennia. This is quite likely for example for the right leg bones of ind. 8 and the left leg bones of ind. 4. In this area at the southeastern fringe, the edge of the mass grave feature could not be determined anymore, as there is evidence for a later disturbance of significant extent (Fig. 1). As both of these legs have been detached at the hip joint, it can be assumed that the bodies had already been skeletonised when this disturbance occurred. Recent mechanical bone damage is evident in several cases, which affected the topmost layer of bones. This damage can in large part be attributed to the routine preparatory utilisation of heavy machinery during the first steps of the excavation before the presence of the mass grave was known.

Fig. 6 Examples of animal damage to the bones from the mass grave. a Typical rodent gnawing damage above the right orbit in the skull of ind. 7. b Carnivore gnawing damage to the distal right tibia in ind. 3, partly overlain by root etching. c Carnivore gnawing damage to the proximal left tibia in ind. 2. Scale bar length is 2 cm Full size image

Stable isotope analyses

Strontium isotope analysis (87Sr/86Sr) on tooth enamel and carbon and nitrogen isotope analyses (δ13C and δ15N) on bone collagen disclosed non-local origins and distinct dietary habits of the individuals interred in the mass grave in comparison to the regular settlement burials at the same site (Fig. 7; Supplementary Tables 2–4). The isotopic composition of strontium, which substitutes for calcium in the hydroxyapatite, depends on the geologic conditions in the area from where food and drink were obtained during enamel formation in childhood. Isotope ratios that differ from local baseline data reveal non-local individuals, while isotopic differences between subsequently formed teeth point to residential changes during childhood38. 87Sr/86Sr ratios were determined for a first and a third molar each from the six individuals where dentitions were available. First molars represent a time span between birth and about 3 years of age, while the crowns of third molars form between about 7 and 14–16 years39.

Fig. 7 Results of the strontium, carbon and nitrogen isotope analyses. Strontium isotope ratios of enamel (a) and carbon and nitrogen isotope data of bone collagen (b) of the individuals from the mass grave in comparison to data from regular LBK and likely LBK settlement burials at Halberstadt. Both analytical methods show the mass grave individuals to be different from the regular interments implying both non-local origins and distinct dietary habits. Individuals subsequently identified as non-LBK have been removed from the settlement burial dataset published previously41 Full size image

The 87Sr/86Sr ratios of the individuals in the mass burial ranged between 0.70841 and 0.71151. While individuals 4, 5, 6, and 8 exhibited more radiogenic 87Sr/86Sr ratios than most of the settlement burials and individual 7 had a rather large difference of 0.00140 between his first and third molar, only the Sr isotope data of ind. 9 were well comparable with those of the settlement burials as a whole (Fig. 7a). Assuming that the regular settlement burials represent the local population, this suggests that the individuals in the mass grave were largely non-local to the site.