Alexandra Bayliss

Pragmatic Bayesians: a Decade of Integrating Radiocarbon Dates into Chronological Models

This chapter is an account of the experiences of the two authors in routinely applying Bayesian statistics to sets of radiocarbon dates. Whereas Buck (Chapter 1) gives an account of the development of the mathematical models, this chapter is concerned with their implementation and routine use. Since the early 1990s radiocarbon data from a large number of archaeological sites have been analysed using Bayesian methods and this chapter provides an overview of the subject from an archaeological perspective. Using examples largely taken from English Heritage projects, the chapter demonstrates the usefulness of the technique, some of the pitfalls and problems encountered and areas for future research. The problems that arise when trying to apply rigorous mathematical methods to very complex models are discussed in relation to the developments of the computer program OxCal. Other perspectives on archaeological chronology building are given by Holst (Chapter 6) and Cichocki et al. (Chapter 4).

The end of the affair: formal chronological modelling for the top of the Neolithic tell of Vinca-Belo Brdo

Abstract Bayesian statistical frameworks have been used to calculate explicit, quantified estimates for site chronologies, and have been especially useful for resolving the complex probability distributions of calibrated radiocarbon dates to the level of individual prehistoric lifetimes and generations. Here the technique is applied to the Neolithic tell of Vinča-Belo Brdo in order to answer long-standing questions about the timing and circumstances of its demise. Modelled date estimates place the end of the site in the second half of the forty-sixth century cal BC. Two successive horizons of closely spaced houses each suffered extensive burning; the interval between them was placed at a maximum of 25 years, with the last house probably used for less than 15 years. The evidence suggests that these house burnings were deliberate, and opens new considerations for the causes of the end of the tell-based system in south-east Europe.

Interwoven strands for refining the chronology of the Neolithic tell of Vinca-Belo Brdo, Serbia

A formally modeled radiocarbon chronology for a new profile through the great Neolithic tell of Vinca-Belo Brdo, Serbia, is the third interwoven strand in refining the chronology of the tell. This now joins models for the whole sequence based on the archive of early excavations, and for the last two known horizons at the top of the settlement mound, investigated in recent decades. In the new deep sounding, Vinca culture occupation from the 52nd century cal BC is slightly later than in the main sequence, probably reflecting the horizontal extension of the tell as it began to grow. The last dated occupation falls in the late 47th–early 46th century cal BC, slightly earlier than in the main sequence, but the top of the profile is affected by the slippage that caused the new excavations. Formal estimates are given for the succession and varying durations of burnt and unburnt houses, and indicate a period in the first part of the 5th millennium without house burning. Overall, the combined results from the three interwoven strands serve to produce a radically enhanced understanding of the temporality of the tell, which builds on, rather than supplants, previous research. We knew previously that Vinca-Belo Brdo was very long-lived, but now we can time that history with much greater precision. We can assert with much greater confidence that its vertical buildup was steady and largely uninterrupted. We have begun, from the work on the top of the tell and in the new deep sounding, to grasp better the fluctuations in house durations from generation to generation, and can now contrast the relative fortunes of unburnt and burnt houses. We can say much more about the timing and tempo of the ending of the tell, and about the possible circumstances in which that took place.

House time: Neolithic settlement development at Racot during the 5th millennium CAL B.C. in the Polish lowlands

The settlement of Racot 18 in the western Polish lowlands is used as a case study in the investigation of continued development and expansion following initial Neolithic beginnings, and in the formal chronological modeling, in a Bayesian framework, of settlement development. The site belongs to the Late Lengyel Culture of the later 5th millennium cal b.c., and represents the intake of new land following earlier initial colonization. The formally estimated chronology for the settlement suggests individual house biographies spanned from as little as a generation to over a century; distinctive substantial buildings from late in the sequence may have lasted longest. Racot 18 is compared to its formally modeled context of the later 5th millennium cal b.c.

Bogs, Bodies and Burnt Mounds: Visits to the Soar Wetlands in the Neolithic and Bronze Age

The recording and analysis of a burnt mound and adjacent palaeochannel deposits on the floodplain of the River Soar in Leicestershire revealed that the burnt mound was in use, possibly for a number of different purposes, at the transition from the Neolithic to the Bronze Age. An extensive radiocarbon dating programme indicated that the site was revisited. Human remains from the palaeochannel comprised the remains of three individuals, two of whom pre-dated the burnt mound by several centuries while the partial remains of a third, dating from the Late Bronze Age, provided evidence that this individual had met a violent death. These finds, along with animal bones dating to the Iron Age, and the remains of a bridge from the early medieval period, suggest that people were drawn to this location over a long period of time.