Kaliska I: a Late Bronze Age metal hoard from Pomerania (Poland)

Abstract In the spring of 2017, amateur metal detectorists discovered a Late Bronze Age hoard near the village of Kaliska, Poland. Comprising over 120 artefacts, it is one of the most impressive Bronze Age finds within Pomerania. The authors discuss the hoard's contents and context, as well as its chronology.


Introduction
Kaliska is a small village near the town of Biały Bór, Szczecinek County, West Pomeranian Voivodeship, Poland. It is situated between the hilly moraines of Pojezierze Szczecineckie and the high moraine hills of Pojezierze Bytowskie, in the highest part of the West Pomeranian Lakeland (Figure 1). In the spring of 2017, a deposit of metal objects was found on agricultural land by amateur metal detectorists. This assemblage is designated Kaliska I, in light of a second discovery of metal objects from the same location, also in 2017.
The Kaliska I hoard comprises 124 artefacts, some of which are organic remains, but most are bronze items, including forged and cast vessels, collars, kidney bracelets and miniature buttons. Several organic artefacts, including a leather strap, spirally formed straps, and an ornament made from spindle wood, were also found loose within a Gevelinghausen-Veio-Seddin type vessel. The state of preservation following conservation is generally good to very good, although the organic objects are fragmentary.
We are currently conducting typological-chronological analyses of all the objects that make up the hoard. In order to provide as comprehensive an investigation as possible, we have prepared a number of specialist analyses of the metal and organic objects, including: metallographic and tracewear analyses; lipid analysis from the bronze vessels; species determinations  for the leather fragments; and archaeometric studies of a pitchy substance-discovered to be wood tar-preserved on one of the bronze ornaments (an appliqué in the form of a rosette), the wooden objects, and the fragments of string preserved on one of the phalerae (Grześkowiak

Dating
The chronological homogeneity of the artefacts is significant and no obviously archaic (i.e. pre-Bronze Age Period V) elements were observed. This can be used to suggest a date for the hoard within Bronze Age Period V (c. 950-800/750 BC). Given that some of the bronze artefacts were possibly used later, however, we can suggest, with caution, that the hoard was probably buried in the second half of Period V, which correlates to the HaB3 phase (c. 875-780/750 BC).
The organic artefacts, however, provide a unique opportunity to determine an absolute chronology for the hoard. Six samples were sent to the PoznańRadiocarbon Laboratory, including two from ornaments made from European spindle (Euonymus europaeus L.), three from fragments of leather and one wood tar sample collected from the inner part of a bronze appliqué.
A Bayesian model (Bayliss 2015) was produced from the resultant dates using OxCal (v.4.4;Bronk-Ramsey 2009a) and calibrated using the IntCal20 calibration curve (Reimer et al. 2020). This model assumes that the Kaliska I hoard is a closed (i.e. chronologically relatively homogeneous) assemblage ( Figure 6). Moreover, the structure of the model considers the accuracy of individual radiocarbon measurements, and thus the possibility of outliers among them (Bronk-Ramsey 2009b). The results indicate that the Kaliska I assemblage was most likely deposited between 790 and 740 BC (at 68.3% confidence, rounded to 10 years) ( Figure 6C). The obtained radiocarbon determinations thus support the relative chronology presented above.

Future work
During the analysis of the Kaliska I hoard, we became aware that another Late Bronze Age assemblage of metal objects had been discovered, possibly lying stratigraphically above the Kaliska I hoard. As a result, the full depositional context, as well as a consideration of the Kaliska hoard in terms of the phenomenon of intensified hoarding observed in Pomerania at the beginning of the first millennium BC, will only be complete with the analysis of this second assemblage, which is currently ongoing.

Funding statement
This research received no specific grant from any funding agency or from commercial and not-for-profit sectors.