4.1 Inhumation graves
The inhumation graves comprise single, double and multiple burials. Single primary burials were most common. From roughly 5500 until 4000 BC most individuals were buried stretched on the back with extended limbs as was attested at Hardinxveld-Giessendam, Swifterbant and Urk. An exceptional custom was observed in one of the graves at De Bruin, where a man had been buried in a sitting position. That same posture is assumed by the excavator for the presumed grave pits at Mariënberg.
The burial posture had completely changed around 3500 BC, at the Middle Neolithic sites of Schipluiden and Ypenburg, to one in which the arms and legs were tightly flexed, sometimes in an extreme way, which can only be explained by the binding of limbs (fig. 3). Also the range of variability in the position of the torso was similar at both sites.
Fig. 3 Ypenburg, burial 13, a tightly flexed adult female individual, characteristic for the Middle Neolithic Hazendonk Group (after Baetsen 2008).
Multiple graves can represent a single deposition or repeated burials at different time intervals. In the case of a single act the deceased were deposited in the grave simultaneously, indicated by the articulation of the skeletons. Overlapping limb bones can show the sequence of deposition as well. The double grave at Schipluiden has the appearance of a single deposition, since both skeletons were articulated, no disturbance was visible and the overlapping of the bones indicates a simultaneous burial (fig. 4). Reasons for primary double or multiple burials can only be guessed at. There is no association with sex or age, so every grave has to be interpreted on its own. The double grave at Schipluiden for instance contained the skeletons of two men. One of them had a severe injury on the skull indicating a violent death. Although the bones of the second individual reveal no traces of the cause of death the simultaneous character of the burial serves as indirect evidence for a violent death of this man as well, implicating – because they were buried in one act – that they probably died at the same time and from the same cause.
Fig. 4 Schipluiden, burial 1, primary double burial of two adult male individuals, Middle Neolithic Hazendonk Group (after Smits & Louwe Kooijmans 2006).
A primary double burial at Ypenburg contained the skeletons of two children and tells a completely different tale. As these skeletons do not display pathological bone changes, possibly an infectious disease of short duration was responsible for the death of both children at approximately the same time.
Repeated primary burials are characterised by a sequence of depositions separated by time intervals, which probably correlated with the time of death of the individuals. The grave was reopened for an additional deposition of a corpse, thereby disturbing the human remains already in the grave. At Ypenburg some burial pits show inarticulate skeletal remains, which may have resulted from this practice. Most obvious is the deviation of the posture of the buried individuals as compared to single burials, and the absence of grave goods. In Urk one of the graves held the remains of three individuals, which seems to be a repeated burial as well. The grave at Zoelen is exceptional because it seems to be a primary grave in the first instance with a secondary deposition on top of it. The secondary nature of the deposition refers to the phenomenon of the (re)burial of a collection of human skeletal remains that were initially buried or exposed at another location.
Underlying factors for the presence of repeated double and multiple burials could relate to social or cultural traditions, practised by for instance kinship groups or immigrants, with specific rules of their own such as the burial of members in a communal grave.