Radiocarbon Dating and Marine Reservoir Correction of Viking Age Christian Burials from Orkney
Barrett, James H., Beukens, Roelf P., Brothwell, Don R., Antiquity
It is uncertain when Christian practice was adopted in Viking Age Scotland. The Western Isles may have been characterized by religious syncretism (Jennings 1998), but northern Scotland -- dominated by the earldom of Orkney -- presents a more complex problem. Two models have been outlined by Christopher Morris (1990; 1996). One takes saga evidence that Earl Sigurd of Orkney was converted in AD 995 as a starting point, but emphasizes the stronger historical evidence that a bishopric was established by Thorfinn Sigurdarson around 1048 (Morris 1990: 18; 1996: 187-8). The second assumes either that Pictish religious institutions survived Scandinavian colonization or that the Norse adopted Christianity from the indigenous population early in the Viking Age (Morris 1996: 187).
The best evidence with which to assess these models includes a 9th-century hagiography (the Life of Findan), ecclesiastical architecture and radiocarbon dates of `Christian' burials. Other lines of evidence, such as Christian sculpture and churches with undated dedications to `Pictish' saints, are also relevant (Lamb 1995; Lowe 1998: 7-8), but lack chronological resolution.
The Life of Findan refers to a bishop in Orkney, around AD 850 (Thomson 1986), lending support to the second model. Given the limitations of hagiography as history, however, it is appropriate to seek corroborating evidence for Christian influence prior to the turn of the 11th century. This paper surveys radiocarbon dates (including 21 new assays) of burials associated with two Orcadian churches which may have 10th-century or earlier phases: the Brough of Deerness and Newark Bay.(1) For these dates to be meaningful, however, they must be adjusted to account for marine reservoir effects using stable carbon isotope data. This is necessary because Viking Age Orcadians relied heavily on marine foods (Barrett et al. 1999), which can bias radiocarbon results -- making them appear older than terrestrial samples of the same age (Tauber 1983; Arneborg et al. 1999). It is given special attention because marine reservoir corrections have rarely been calculated for human bone from Scotland. The results contribute to the growing body of evidence that Christian practice may have pre-dated the traditional conversion of 995.
The identification of `Christian' graves and buildings presents epistemological difficulties (e.g. Abrams 1998). Here it is assumed that the co-occurrence of supine east-west oriented burials, an east-west oriented structure (lacking domestic or industrial features such as a hearth) and the absence of grave-goods from all or virtually all graves is sufficient to imply the existence of a church and associated cemetery.
The Brough of Deerness (Morris & Emery 1986) and Newark Bay (Brothwell 1977) are located in the east Mainland of Orkney (FIGURE 1). Two superimposed chapel phases were identified at Deerness by Morris & Emery (1986). The later is of stone construction; the earlier of timber with stone cladding. Both phases were associated with only a small number of graves and appear to have been private chapels in a chiefly stronghold (Morris & Emery 1986; Morris 1996). A worn coin of Eadgar (reign 959-975) found under the floor of the stone chapel provides a terminus post quem for it and a terminus ante quem for the earlier timber phase (Morris & Emery 1986; Morris 1996: 192). The timber phase could be pre-Viking, but is more likely to belong to a Norse milieu based on architectural characteristics (Morris & Emery 1986; Morris 1996). Two radiocarbon dates exist for burial BS (the only skeleton preserved sufficiently for analysis), which stratigraphically post-dates the stone phase.
[Figure 1 ILLUSTRATION OMITTED]
At Newark Bay, a rectangular stone building (oriented approximately east-west) was excavated beneath late medieval and post-medieval deposits. The internal dimensions of the nave were 4. …