Bayesian chronology construction and substance time

Two views of archaeological time are distinguished; an event view that models stratigraphic relations, and a substance view that models genealogical relations among artifacts, including the three modes of change represented by branching, transformation, and reticulation. Chronology construction is more complex in substance time than it is in event time, which only concerns transformation. Allen's interval algebra can be used to specify the chronological relations associated with the modes of change, and these relations can be identified by post-processing the output from Bayesian chronological models. A worked example illustrates how identifying the chronological relations can aid construction of a phyletic seriation of beads recovered from Anglo-Saxon female graves. These results might encourage archaeologists to carry out chronology construction in substance time as an aid to historical inference. •Bayesian methods can construct site chronologies and artifact genealogies.•Time reckoning differs between site chronologies and artifact genealogies.•ArTifact genealogies are more complex than site chronologies.•Allen's interval algebra is an aid to constructing artifact genealogies.•Bayesian models must take care to separate site chronologies from artifact genealogies.