Archaeological cross dating: a formalized scheme

Cross dating is the standard method by which archaeologists date archaeological contexts of unknown age based on parallel contexts of known age. Despite its importance, archaeological cross dating apparently still lacks proper mathematical modelling and a precise methodology. This paper proposes a formal definition of cross dating and discusses its complexity and limitations. We define the concept of “chronological propagation” between time periods and characterize its mechanism in terms of various types of synchronisms. We discuss the notion of archaeological contemporaneity, we define its inherent limitations for performing cross dating and we propose two practical solutions to deal with these limitations. We then present a comprehensive scheme for modelling real-life cross dating applications, based on the recent ChronoLog software (chrono.ulb.be). Finally, we illustrate these concepts by a practical case study from Aegean Bronze Age archaeology: Tomb 4 at Sellopoulo (Crete) and its rich assemblage linking the chronologies of Crete, Mycenaean Greece and Egypt.